Assessing SMEs’ Internationalisation Strategies in Action

In this paper, a structured review was conducted to investigate the internationalisation process of small and medium enterprises (SMEs) to define barriers and enablers and identify research gaps in this relevant field. Data were collected from two databases of scientific peer-reviewed articles (i.e., Scopus and Web of Science). After the selection process, 161 papers focusing on SMEs’ internalisation were analysed using both descriptive and content analysis. The analysis of the results highlights that SMEs’ internalisation is a growing research field, but different research gaps remain to be filled. These gaps concern barriers, impact on performance, models, and theories related to the different phases of the internationalisation process (e.g., start-up, early entrance, international growth). The future research directions identified interesting suggestions and guidelines for future researchers in the field of SMEs internationalisation.


Introduction
Previous literature highlights the pivotal role of globalisation in the competitiveness of small and medium enterprises (SMEs) which results in an increasing effort in managing SMEs' internationalisation processes [1,2]. The efficiency and effectiveness of these processes are directly related to the way SMEs manage their internationalisation-related information [3,4] and their internationalisation-related knowledge [5,6] to internationalize their business activities. Within this scenario, previous studies have shown that the internationalisation of business activities is more complicated for SMEs than large firms [7,8]. Consequently, the recent literature has focused on the barriers and risks hindering SMEs to enter new foreign markets. A variety of specific factors hindering the internationalisation of SMEs have been previously explored empirically, analysing environmental, financial, operational and Organisational barriers [9,10]. Previous literature has shown that SMEs are more successful in internationalizing their business when they leverage on strong internal resources or if they receive incentives and/or support from external sources. Furthermore, a rather new research direction aims to explore the critical success factors affecting the process of internationalisation of SMEs positively. Specifically, several contributions have previously analysed how SMEs can be supported in their internationalisation process by external partners [11], local target-country partners [12], home-country partners and institutions that provide consulting services or foreign-trade promotion [13]. Within this evolving scenario, a systematic review analysing the different topic areas investigated in the body of literature (i.e., factors influencing internationalisation, internationalisation models, internationalisation barriers and the impact of internationalisation on performance) and the specificity of the diverse phases of internationalisation of an SME (start-up, early entrance and international growth) still seems to be neglected. These two perspectives of analysis are crucial and highlight important additional issues. The factors influencing the process of internationalisation in the various phases are not necessarily the same. These factors include aspects related to changes in SMEs with a view to Industry 4.0. Businesses are changing by introducing industry 4.0 technologies, such as cyber-physical systems, cloud computing or visual analytics, that may be linked to bringing transparency to the industry, increasing sustainability [14]. Besides, vertical integration, holistic life-cycle management, horizontal integration through value networks and sustaining innovative product design is among the most pressing challenges for SMEs [15,16]. Even internationalisation models adopted are different. Nevertheless, the different phases of the process of internationalisation of an SME remain an underexplored area of research.
Thus, the main aim of this paper was to discuss SMEs' internationalisation processes. This paper finds a place in the emerging debate regarding whether regular business-to-business ties with companies can intensify the internationalisation process of SMEs. With these premises, this paper aimed to conduct a literature review on the topic of internationalisation of SMEs. This review extends the body of knowledge on business management and internationalisation domains: (i) investigating the impact of the thematic areas described above in the internationalisation process of SMEs, with particular attention on decision-making; (ii) detecting the research gaps to be further investigated in the existing literature.
With these premises, the remainder of the paper is organized as follows. Section 2 presents the methodology used to conduct the review and presents the five-step approach used to analyse the literature on the topic. Section 3 discusses the findings of the structured literature review (SLR). Section 4 summarizes the results of the analysis presenting significant research insights and suggestions. Finally, relevant research directions to be further investigated and some limitations of the paper are presented.

Methodology
In this paper, a structured review methodology adapted by Tranfield et al. (2003) [17], Pittaway et al. (2004) [18], and   [19] has been used [17][18][19]. A structured review is a well-known approach adopted to provide a detailed overview of a given topic able to reduce research biases using a replicable and transparent process (Tranfield et al. (2003) [17]). This approach is particularly suitable when reviewing qualitative topics, such as internationalisation in SMEs, and allows researchers to provide an in-depth understanding of qualitative aspects. With these premises, our structured review is organized into two principal phases divided into two steps.

1.
Phase of papers acquisition and selection: (a) Material search: In this step, keywords, search strings, and databases to be examined (i.e., Scopus, Web of Science) were identified; (b) Selection: In this step, criteria for inclusion/exclusion and the selection process based these criteria were defined.

2.
Phase of descriptive and content analysis of the selected papers: (c) Descriptive analysis: In this step, the papers were analysed according to different perspectives; (d) Content analysis: The full text of the papers selected were analysed in depth. As a result, the main research areas were discussed, and research gaps and appropriate research questions to be investigated were formulated.

Phase of Material Search
This phase aimed to identify relevant contributions on the topic of internationalisation in SMEs. The search was conducted using both Scopus and Web of Science databases, retrieving papers published from 1995 to 2019. The initial search string of keywords was identified through a focus group involving four researchers and included this list of keywords: "small and medium enterprise*", "SME*", "small firm*", "small business*" in combination with "internationalisation".
Additional criteria were identified to select the relevant contributions: • Only papers published in peer-reviewed journals were included in the review process [20]; • Only papers belonging to Business, Management and Accounting, Decision Sciences, Engineering, Environmental Science and Social Sciences subject areas were chosen [21].
Successively, the search string was validated, analysing the keyword occurrences of the papers retrieved. Keywords used by more than 30% of the papers were included in the search string. The final search string used was: ("small and medium enterprise*" OR "SME*" OR "small firm*" OR "small business*") AND ("internationalisation" OR "internationalisation").
All the articles that met the criteria of potentially relevant articles were collected. A total of 398 and 284 papers were retrieved from Scopus and Web of Science, respectively, resulting in 581 unique papers excluding duplications.

Phase of Selection
Three selection criteria (i.e., two exclusion criteria and one inclusion criterion) were identified to focus on the research to the topic under investigation ( Table 1). The first exclusion criterion made it possible to identify relevant papers analysing their abstract [18]. Following   [19], the abstracts of the 581 papers were read by two researchers and, in the case of uncertainty, by a third researcher, defining three lists (Table 2):

•
List A: papers that had abstracts focusing on the concept of internationalisation and where the unit of analysis was SMEs; • List B: papers which had abstracts mainly focusing on internationalisation, but made scarce or insignificant reference to SMEs; • List C: papers which had abstracts mainly focusing on SMEs, but made scarce or inconsiderable reference to the topic of internationalisation [22].  The papers indexed in List B (140 papers) and List C (100 papers) were excluded, as they were beyond the primary aim of this review. Conversely, the full text of the 341 papers indexed in List A was analysed in detail by two researchers (i.e., second exclusion criterion). A total of 181 papers (out of 341) were excluded from the sample since not focused on the topic under investigation.
The third inclusion criterion allows the authors to identify additional papers to be included in the sample, thus analysing the papers' references. This last criterion allowed the authors to include one additional paper leading to a sample of 161 papers.

Phase of Descriptive Analysis
The descriptive analysis aimed to provide an overview of the papers focusing on the issue of internationalisation in SMEs. For the descriptive analysis of the 161 papers in the final sample, the following viewpoints were identified:

•
Papers by year; • Papers by country; • Papers by methodology; • Papers by topic area; • Papers by process.

Papers by Year
In this analysis, we investigated the annual scientific distribution of collected papers. Figure 1 shows how the interest of the scientific community on the subject began to have significant growth starting from 2009.

Phase of Descriptive Analysis
The descriptive analysis aimed to provide an overview of the papers focusing on the issue of internationalisation in SMEs. For the descriptive analysis of the 161 papers in the final sample, the following viewpoints were identified: • Papers by year; • Papers by country; • Papers by methodology; • Papers by topic area; • Papers by process.

Papers by year
In this analysis, we investigated the annual scientific distribution of collected papers. Figure 1 shows how the interest of the scientific community on the subject began to have significant growth starting from 2009.

Papers by country
In this analysis, we investigated the papers published by the authors' countries. The analysis shows the leading role of some European countries with more than half of production. Figure 2 reports the number of papers published by top 10 authors' countries. Figure 2 shows the related weight in the global production revealing the dominance of the USA and the role of United Kingdom

Papers by Country
In this analysis, we investigated the papers published by the authors' countries. The analysis shows the leading role of some European countries with more than half of production. Figure 2 reports the number of papers published by top 10 authors' countries. Figure 2 shows the related weight in the global production revealing the dominance of the USA and the role of United Kingdom (10.63%), Italy (9.38%) and Portugal (8.13%) as leading countries.

Papers by methodology
The methodologies adopted by the papers were categorized in quantitative, qualitative, theoretical and mixed approaches. Figure 3 highlights that the majority of papers (80) adopt quantitative methodologies (i.e., mathematical models, surveys and simulation model). As regards the surveys, they differ in the way how data were collected: face-to-face mode, online form and e-mail. The percentage of face-to-face interviews highlights the qualitative nature of the topic. The 39 papers based on qualitative methodologies are based on single or multiple case studies. The conceptual papers (33)

Papers by Methodology
The methodologies adopted by the papers were categorized in quantitative, qualitative, theoretical and mixed approaches. Figure 3 highlights that the majority of papers (80) adopt quantitative methodologies (i.e., mathematical models, surveys and simulation model).

Papers by methodology
The methodologies adopted by the papers were categorized in quantitative, qualitative, theoretical and mixed approaches. Figure 3 highlights that the majority of papers (80) adopt quantitative methodologies (i.e., mathematical models, surveys and simulation model). As regards the surveys, they differ in the way how data were collected: face-to-face mode, online form and e-mail. The percentage of face-to-face interviews highlights the qualitative nature of the topic. The 39 papers based on qualitative methodologies are based on single or multiple case studies. The conceptual papers (33)   As regards the surveys, they differ in the way how data were collected: face-to-face mode, online form and e-mail. The percentage of face-to-face interviews highlights the qualitative nature of the topic. The 39 papers based on qualitative methodologies are based on single or multiple case studies. The conceptual papers (33) included in the sample are based on previous theoretical approaches and use secondary data and information. Finally, 9 papers combine qualitative and quantitative methodologies.

Papers by Topic Area
Papers are clustered according to four topic areas identified to get a full overview of the body of literature: • "Factors influencing internationalisation", in which main critical success factors (CSFs) related to the process of internationalisation of SMEs are identified; • "Internationalisation models", in which the appropriate theoretical models and paradigms used to analyse the internationalisation of SMEs are presented; • "Internationalisation barriers", in which the main factors hindering the process of internationalisation of SMEs are identified; • "Impact of internationalisation on performance", in which it is shown the relationship between internationalisation and SME's performance.
The results highlights that "factors influencing internationalisation" was the topic area with the highest number of papers (74), "Impact of internationalisation on performance" included 35 papers, "Internationalisation models" included 31 papers and "Internationalisation barriers" included 21 papers.

Papers by Process
In line with Johanson and Mattsson (1988), Johanson and Vahlne (1990), and Johanson and Vahlne (2009), papers are clustered according to the three main phases characterizing the process of internationalisation of SMEs: the phase of international extension, in which the SME starts to build the international network; the phase of international penetration, in which the SME develops its position in the network and increases the resource commitment; and the phase of international integration, in which the SME consolidates its position in the international network [23][24][25].

Phase of Content Analysis
Content analysis of 161 papers aims to provide a comprehensive understanding of the SMEs' internationalisation.
This analysis identified two main content perspectives: the topic area (i.e., factors influencing internationalisation, internationalisation models, internationalisation barriers, and the impact of internationalisation on performance) and the phases of the internationalisation process (i.e., extension, penetration, and integration) ( Table 3). The intersection between the topic areas and the phases of the internationalisation process enabled authors to identify and underline 12 content areas. The areas identified are: Area 1: Factors influencing international extension (18). Area 2: Factors influencing international penetration (16). Area 3: Factors influencing international integration (40). Area 4: International extension models (8). Area 5: International penetration models (10). Area 6: International integration models (13). Area 7: International extension barriers (9). Area 8: International penetration barriers (4). Area 9: International integration barriers (8). Area 10: Impact of international extension on performance (3). Area 11: Impact of international penetration on performance (3). Area 12: Impact of international integration on performance (28).

Area 1: Factors influencing international extension
The first area includes 18 articles and focuses on factors influencing the first phase of the internationalisation process. Following is a description of the study's objective, the methodology used, and the results obtained.
García-Cabrera et al. (2016) [26] analysed how SMEs entrepreneurs' perception influences the decision to expand their business operations internationally. Researchers collected data from 296 Brazilian SMEs and used multiple linear regression analysis. Findings confirmed that entrepreneurs' perception of regulative and normative aspects of institutions positively affects SMEs' internationalisation expansions. Oura et al. (2016) [27] compared the influence of international experience and innovation capacity on SMEs' export performance using structural equation modelling. Findings inferred that international experience dramatically influences to the export performance than innovation capacity.  [29] claimed that individual global mindset and the company's global mindset affect the SMEs' internationalisation behaviour. Moreover, literature advocated management commitment and experiential knowledge as highly important factors for successful internationalisation and also, to improve SMEs' adaptation efforts and overall performance [30]. Using the simulation method, Stouraitis and Kyritsis (2016) [31] claimed that first the exporting choice influence later exporting choices, and home country-specific, internal, and motivators significantly affect first and later exporting choices. Hilmersson et al. (2015) [32] analysed nine case studies and reported that experience, network structure and ability to analyse international opportunities favour the international expansion process. Similarly, public financial support is a significant factor that influences the internationalisation of SMEs as public incentives intervene positively on sales and production growth, especially for small businesses and young people [33]. In addition to those already mentioned by Hilmersson, Child et al. (2014) [3] used a qualitative approach and advocated the importance of the information flow. Shirokova and Tsukanova (2013) [34] derived data from the Business Environment and Enterprise Performance Survey and analysed using regression. The authors pointed out that tax rates and corruption affect the pre-Start-up phase of the internationalisation process. Senik et al. (2011) [35] interviewed 54 SMEs owners and identified that sources of internationalisation intelligence significantly affect to internationalisation, as the firms need a variety of information about international markets and regulatory frameworks. In the same vein, Miočević et al. (2011) [36] investigated the impact of information and cognitive-based capabilities in the Croatian exporting SMEs' international performance. They used 125 exporting SMEs as a sample, and PLS structural modelling was used for hypothesis testing. Results affirmed that information and cognitive-based capabilities significantly influence SMEs' export performance. Besides, Sommer et al. (2010) [37] used stepwise regression analysis and concluded that the cognitive aspects increase the knowledge of decision-making about SMEs internationalisation. Ruzzier et al. (2007) [38] collected 165 responses from Slovenian internationalized firms and analysed using structural equation modelling. The results indicated that international business skills, international orientation, organisational perception and management have a significant positive impact on SMEs' internationalisation. Meanwhile, Liesch et al. (1999) [39] conceptualized the role of information in internationalisation development. Ooi and Richardson [40] explored the internationalisation of service-sector SMEs from an emerging market, focusing on psychic distance, business network, internationalisation challenges and capabilities of business training and consultancy firms from Malaysia.
In summary, the literature that focuses on this area highlights a variety of factors that influence the phase of international extension. These factors were classified into four main categories: managerial factors (e.g., equipment quality, production technology, management, and know-how); relational factors (e.g., cooperation, conflicts, partnership, contracts and joint ventures); environmental factors (e.g., technology uncertainty, uncertainty, and dissimilarity); and socio-political factors (e.g., socialization, institutional contest).
Ultimately, the authors who did the work on the factors influencing the phase of international extension, they analysed all the variety of factors: managerial, relational, environmental and socio-political. It follows, therefore, exhaustive literature about this area. We propose in Table 4 a summary overview of the topics covered by the work of the authors examined.

Area 2: Factors influencing international penetration
The second area includes 16 articles and focuses on factors influencing the second phase of the internationalisation process. Following is a description of the study's objective, the methodology used, and the results obtained.
Langseth et al. (2016) [43] analysed eight SMEs cases and identified four forces (i.e., technology, globalisation perception, knowledge of foreign markets, and networks) that influence the early internationalisation. Game et al. (2016) [44] explored the impact of SMEs' decision-makers' attitude on internationalisation development. In doing so, 3117 responses collected form Canadian manufacturing-based SMEs were analysed using regression technique that validated the impact of decision-makers' attitude in the decision-making process for SMEs internationalisation development.  [51] surveyed 2657 Italian manufacturing firms that confirmed product innovation positively influences SMEs' export performance. Moreover, researchers did not find any evidence that can advocate experience as a guarantee of success in neither in regional nor in foreign markets. Miočević et al. (2012) [52] developed a squares model on a data sample of 121 Croatia based exporting SMEs. Results stressed that the firm's global mindset affects the success of internationalisation development, and there is a significant interwoven between international experience and international performance. Maekelburger et al. (2011) [53] studied the input mode and their evolution in the international market by analysing the case studies of 206 German SMEs. The study found that the dynamics are significant due to the limited international experience, but above all, the concept of efficiency is highly important to meet the constraints of available resources. Xie et al. (2009) [54] examined the effect of social networks on strategic choices, competitive decisions, and marketing strategies. In doing so, researchers interviewed Chinese SME entrepreneurs and concluded that cultural and ethnic factors play an essential role in internationalisation success surprisingly. Ramelet et al. (1999) [55] examined the role of the internet in SME internationalisation development. For this purpose, multiple case studies were analysed, and finding pointed out that the internet is not only as a way to break down the entry barriers but also a new international strategy to improve the efficiency and competency. Sadeghi et al. (2019) [56] executed a comparative analysis of cases from Italy and Iran to find universal factors, others that are Iranian context-based and one factor specific to the Italian context.
In summary, the literature that focuses on this area highlights a variety of factors that influence the phase of international penetration. These factors were classified mainly into four categories: managerial factors (e.g., equipment quality, production technology, management, and know-how); relational factors (e.g., cooperation, conflicts, partnership, contracts, joint venture); environmental factors (e.g., technology uncertainty, uncertainty, dissimilarity); socio-political factors (e.g., socialization, institutional context).
Ultimately, the authors who have done work on the factors influencing the phase of international penetration analysed all the variety of factors: managerial, relational, environmental and socio-political. It follows, therefore, exhaustive literature about this area. We propose in Table 5 a summary overview of the topics covered by the work of the authors examined.

Area 3: Factors influencing international integration
The third area includes 40 papers and focuses on factors influencing the third phase of the internationalisation process. Following is a description of the study's objective, the methodology used, and the results obtained.
Onkelinx et al. (2016) [59] used a dataset of Belgium's manufacturing SMEs which internationalized between 1998 and 2005 to investigate the level of human capital in internationalisation strength. The result indicated an "inverted U" relationship between the level of human capital and export intensity. Agostini (2016) [60] reported different structures, processes, and tools that are used to create new knowledge for the internationalisation. The study found that integrated learning and strong network enable the firm to explore unprecedented international market opportunities. Zhang et al. (2016) [61] analysed multiple SMEs cases and claimed that the institutional environment has a high impact on the firm's international performance. Through an exploratory survey of Italian SMEs, Veglio et al. (2015) [62] stressed that only design innovation has a positive impact on the firm's internationalisation process. Ismail et al. (2015) [63] used complementary theories and advocated proper knowledge about the internal and external factors along with the existing scope level in foreign markets that have immense value in shaping SMEs' performance. Besides, SMEs operating in a higher number of regions showed better international performance as compared to those operating in a lower number of regions. Ginting (2015) [64] used structural equation modelling techniques to analyse the data collected from Indonesian SMEs and found that network resources utilization positively associated with the degree of internationalisation and firm performance. Besides, no association was found between the degree of internationalisation and firm performances. Sandberg (2014) [65] examined the impact of three different types of knowledge (i.e., general internationalisation knowledge, market-specific knowledge and customer-specific knowledge) on the SMEs network configuration in the internationalisation process. Logistic regression analysis pointed out that the only market-specific and customer knowledge has a significant impact on the SMEs network configuration. Using a theoretical approach, Garg [76] affirmed that the firm size, international experience, distinctiveness, and innovation have a direct impact on the degree of SMEs internationalisation. Melén (2010) [77] used structural equation modelling technique on data collected from 188 Swedish SMEs and concluded that the intensity of knowledge has direct positive effects on the development of knowledge on foreign customers' needs, requirements and ways of solving problems. Tunisini et al. (2009) [78] analysed multiple case studies of Italian SMEs and pointed out that a strong relationship with local suppliers plays an important role in the critical stages' internationalisation. Knight et al. (2009) [79] studied the factors that support SMEs' performance in international markets by analysing case studies. The study concluded international orientation, international marketing expertise, international innovativeness and international market orientation as main drivers of paramount performance. Bradley et al. (2006) [80] tested dependency of the supplier-customer relationship by using regression analysis on survey data collected from customers and suppliers related to the computer industry. The analysis revealed that the relationship depends upon the length of experience, and the long experience builds a positive attitude. Ibarra-Morales et al. (2019) [81] boosted the internationalisation of companies by implementing key factors that will help them to increase their exports in a context of an emerging country such as Mexico, where very few SMEs achieve internationalisation. Bonfim et al. (2018) [82] investigated managerial risk perception regarding the internationalisation of small and medium-sized enterprises in the Brazilian context. They examined how managers' perception of risk influences firms' degrees of internationalisation. Rubino et al. (2017) [83] analysed, through an empirical study, the Italian network agreements to evaluate how the activities and attitudes of the network managers impact on export intensity. In the same field of export initiatives, Gutiérrez-Artacho and Olvera-Lobo [84] investigated the network promotion role of export promotion programs in driving SMEs' export performance.
In summary, the literature that focuses on this area highlights a variety of factors that influence the phase of international integration. These factors were classified into four main categories: managerial factors (e.g., equipment quality, production technology, management, know-how); relational factors (e.g., cooperation, conflicts, partnership, contracts, joint venture); environmental factors (e.g., technology uncertainty, uncertainty, dissimilarity); socio-political factors (e.g., socialization, institutional contest).
Ultimately, the authors, who have done work on the factors influencing the phase of international integration, have analysed all the variety of factors: managerial, relational, environmental and socio-political. It follows, therefore, exhaustive literature about this area. We propose in Table 6 a summary overview of the topics covered by the work of the authors examined.

Area 4: International extension models
The fourth area includes eight papers and focuses on internationalisation models of the first phase of the internationalisation process. Following is a description of the study's objectives, the methodology used, and the results obtained.
Zapletalová (2015) [102] proposed a multi-level integrated theoretical framework and discussed managerial, product life cycle, strategy, and resource-based views for internationalisation. Basly (2007) [5] investigated the internationalisation of family SMEs. The researcher collected data from 118 companies belonging to different industrial sectors, and hypotheses were tested using structural equation modelling. It came out that knowledge of internationalisation positively influences the degree of internationalisation, while the conservatism of the family SMEs does not directly influence the level of internationalisation knowledge. Matlay et al. (2006) [103] conducted a literature-based study and conceptualized that entrepreneur human capital, firm characteristic and environmental characteristics directly affect SMEs' internationalisation which further affects firm performance.
Belhoste et al. (2019) [104] developed theoretical propositions that extend existing models about support services and firm internationalisation.
In summary, the literature that focuses on this area highlights a variety of internationalisation models for the international extension phase. The models were classified into three main categories: decision models (e.g., rational, bureaucratic, administrative), behavioural models, and operating models (e.g., organization of resources, skills).
Ultimately, the authors, who have done work on the internationalisation models for the international extension phase, have analysed all the variety of internationalisation models: decision models, behavioural models, and operating models. It follows, therefore, exhaustive literature about this area. Table 7 presents an overview of the topics covered by the papers examined. Table 7. International extension models.

Area 5: International penetration models
The fifth area includes 10 papers and focuses on internationalisation models of the second phase of the internationalisation process. Following is a description of the study objectives, the methodology used, and the results obtained.  [107] studied the issues related to international market selection and entry model selection. With the semi-structured questionnaire, a total of 221 Italian SMEs was interviewed, and further a logistic regression analysis was used. Results inferred that SMEs have a non-systematic and passive behaviour during international market selection and entry model selection. Using grounded theory, Thai et al. (2013) [108] pointed out that the current experience largely influences SMEs' internationalisation in comparison to experience(s). Sandberg (2013) [109] conceptualized entry node (triad via the home market; triad via the host market; dyad from the home market; and dyad at the host market) of SMEs in the emerging markets. The proposed hypothesis was tested employing ANOVA on data collected from 197 Sweden SMEs. Findings confirmed that after initial entry, one-third of the SMEs changed their nodes, primarily into a more committed node. Furthermore, Hagen et al. (2012) [110] used the regression technique and advocated that consistent, transparent and proactive strategic orientation leads towards paramount international performance. In literature, empirical evidence is also available that export has a positive impact on internationalisation growth, but a negative impact on profitability, while, foreign direct investment has a positive impact on internationalisation growth but a U curve relationship with profitability [111]. Wolff et al. (2004) [112] examined the relationship between SMEs' export competitive patterns and companies' resources and characteristics. In doing so, data were collected from 157 export-active small firms and further analysed using multiple regression methods. Results provided mixed agreement for hypothesized relationships. Cafferata et al. (1995) [113] built a taxonomy of SMEs and claimed that taxonomy could assist in identifying the proper connections between supply and demand. Uthamaputhran (2018) [114] developed a new theoretical model that helps to understand the entrepreneur's decision to use of different resources to create means and speed up the process of sensing and shaping the international opportunities.
In summary, the literature that focuses on this area highlights a variety of internationalisation models for the international penetration phase. The models were classified into three main categories: decision models (e.g., rational, bureaucratic, administrative), behavioural models, and operating models (e.g., organization of resources, skills).
Ultimately, the authors who published papers on the internationalisation models for the international penetration phase analysed all the varieties of internationalisation models: decision models, behavioural models, and operating models. It follows, therefore, exhaustive literature about this area. We propose in Table 8 a summary overview of the topics covered by the work of the authors examined. Table 8. International penetration models.

Area 6: International integration models
The sixth area includes 13 papers and focuses on internationalisation models of the third phase of the internationalisation process. Following is a description of the study's objectives, the methodology used, and the results obtained. Ciravegna et al. (2014) [7] examined how SMEs develop and use their networks to penetrate their first foreign market. Researchers interviewed the founders of 58 high-tech SMEs and reported customer-supplier relationships, personal contacts and contacts build through existing strategies as network building mechanisms for the first export. Seifriz et al. (2014) [115] collected data from 71 German manufacturing SMEs and concluded that the strength of social networks contributes to successful international integration. Schweizer (2013) [116] offered a process description of how SMEs successfully create networks that lead to their international expansion and discussed four interrelated phases associated with secure networks. Administering a multi-case study related to Iran's information and communication technology industry, Zarei et al. (2011) [117] proposed the best practices network model to facilitate SMEs' entry, survival and growth in global markets. Mainly, this model offers a broad overview of the best practice network in terms of product, customer interface, infrastructure management, and financial aspects. Mejri et al. (2010) reviewed existing literature and identified market knowledge, experiential knowledge, network knowledge, cultural knowledge, and entrepreneurial knowledge as essential for SMEs' internationalisation [118]. Raymond et al. (2005) [119] obtained data of 201 Canadian manufacturing SMEs and further proposed hypotheses were tested employing structural equation modelling. Results statistically confirmed that the level of owner/manager's education and industrial experience affects the firm's strategic development. Likewise, network development positively influences market development; and both market and product development positively influence firm growth. Igartua et al. (2018) [120] designed a tool as an agile way to assess the maturity of a firms innovation approach and a practical first-step to focus innovation management in the strategically right areas, and to establish action plans to advance in the achievement of established objectives, and fostering an organisational learning approach. Ribau et al. (2017) [121] proposed a conceptual model that analyses the factors influencing the export performance of SMEs and integrates international entrepreneurship theory and international strategies.
In summary, the literature that focuses on this area highlights a variety of internationalisation models for the international integration phase. The models were classified into three main categories: decision models (e.g., rational, bureaucratic and administrative), behavioural models, and operating models (e.g., organization of resources and skills).
Ultimately, the authors who have done work on the internationalisation models for the international integration phase analysed behavioural models and operating models. It follows, therefore, a gap concerning the decision models understood treatment as the management approaches of the decisions in the phase of integration. We propose in Table 9 a summary of the topics covered by the articles of the authors examined. Table 9. International integration models.

Area 7: International extension barriers
The seventh area includes 9 papers and focuses on international extension barriers. Following is a description of the study's objective, the methodology used, and the results obtained. Makhmadshoev et al. (2015) [127] compared the influence of national institutional environments on the internationalisation of SMEs exporters from Tajikistan and Kyrgyzstan. The case study analysis suggests significant differences in the institutional environments facing SMEs exporters in the countries. Especially, SMEs exporters in Tajikistan seem to experience more stringent institutional constraints relative to their Kyrgyzstan counterparts, and this divergence in institutional environments appears to affect the internationalisation prospects and competitiveness of SMEs exporters adversely and favourably, respectively. Ahmad (2014) [128] used both qualitative and quantitative method(s) to identify the key drivers and main barriers that can hamper the international growth of Malaysian SMEs. In doing so, 216 SMEs engaged in international business were surveyed, and 25 SMEs owners/managers were interviewed. Findings reported that the motives of international expansion varied among SMEs. Nevertheless, SMEs still face many institutional challenges that have confined firms from attaining paramount performance. Hutchinson et al. (2009) [129] investigated the initial internationalisation barriers experienced and perceived by small retailers based in the UK. Findings from case studies reported barriers related to the management (lack of vision, fear of losing control, and the lack of knowledge), related to the company (transfer of detail of the concept abroad, lack of resources, and lack of consolidation in the domestic market), and related to the external environment (legislation, currency, cultural differences, and logistics). Moskowitz (2008) [130] studied the changing patterns about SMEs' internationalisation in Western Europe towards Eastern European economies in transition, and why some industries in some countries are 'stuck' in the initial stages of internationalisation. In this context, the EU's role was found both nutriment and barrier source in the SMEs internationalisation. Lam-González et al. (2019) [131] analysed factors constraining the international growth of island-based nautical tourism organisations. For the research, a sample of 60 nautical tourism SMEs was interviewed.
The study provided information about current conditions and barriers to the internationalisation process within the segment and also identify the profile of the firms with the best international performance. Rahman et al. (2017) [132] analysed the decision to enter a foreign market considering resource limitation. This study has used primary data collected through questionnaires from 212 Bangladeshi SMEs.
In summary, the literature that focuses on this area highlights a variety of internationalisation barriers for the international extension phase. These barriers were classified into four categories: socio-political barriers (e.g., institutional, and political), environmental barriers (e.g., uncertainty, and dissimilarity), market barriers and barriers related to resources (e.g., technology and human resources).
Ultimately, the authors who have done work on the internationalisation barriers for the international extension phase analysed all the varieties of internationalisation barriers: socio-political barriers, environmental barriers, market barriers and barriers related to resources. It follows, therefore, exhaustive literature about this area. We propose in Table 10 a summary of the topics covered by the work of the authors examined. Table 10. International extension barriers.

Area 8: International penetration barriers
The eighth area includes four papers and focuses on international penetration barriers. Following is a description of the object of the author's analysis, the methodology used, and the results obtained.
Hilmersson et al. (2015) [32] analysed 203 SMEs' responses using a regression technique to investigate the political sources of uncertainty in the SMEs internationalisation process. Findings galvanized that political turbulence increases the uncertainty; therefore, an entrepreneur's political knowledge can minimize the uncertainty level in the internationalisation process. Meanwhile, political turbulence increases uncertainty by reducing political knowledge. Gardo et al. (2015) [136] carried in-depth experts' interviews to identify the barriers faced by Spanish retailers during internationalisation. The results show that there is a predominance of endogenous barriers than those of exogenous origin and that the current international economic climate is characterized by limited access to finance. Tuzová et al. (2017) [137] examined resilience and non-resilience barriers faced by SMEs in a developing country. In addition to the resilience literature, they examined non-resilience and combine its characteristics with resilience barriers from the Bangladeshi context.
In summary, the literature that focuses on this area highlights a variety of internationalisation barriers for international penetration phase. These barriers were classified into four categories: socio-political barriers (e.g., institutional, and political), environmental barriers (e.g., uncertainty and dissimilarity), market barriers and barriers related to resources (e.g., technology and human resources).
Ultimately, the authors who have carried out work concerning the internationalisation barriers regarding the international penetration phase, analysed the market barriers, the environmental barriers, and socio-political barriers. There is a gap regarding the treatment of the barriers related to resources in the penetration phase. Table 11 shows the classification of the topics covered by the papers examined. Table 11. International penetration barriers.

Area 9: International integration barriers
The ninth area includes eight papers and focuses on international integration barriers. Following is a description of the object of the author's analysis, the methodology used, and the results obtained. Tangkittipaporn et al. (2009) [139] surveyed 141 foreign and Chinese-owned exporting SMEs located in China to identify the international trade competencies and export barriers between the highly successful SMEs and low successful SMEs. The analysis found financial management at the highest level of competency, which was further followed by marketing, export operations, and human resource management, respectively. Whereas, government export policy and treatment have emerged as dominant barriers. Pietrasieński et al. (2015) [140] studied the barriers which frequently hinder SMEs' efforts of international market expansions. In doing so, a total of 40 barriers was identified, which were further categorized into 10 groups. Venkatesh et al. (2015) [141] conducted a qualitative study and analysed Indian textile SMEs. They categorized the main internationalisation drivers and barriers related to SMEs' international development. Likewise, Nagy (2013) proposed a theoretical framework about the recent trends in Spanish SMEs internationalisation [142]. Hutchinson et al. (2009) [129] adopted a qualitative methodology to build an understanding of the significant barriers in international expansion faced by SMEs UK retailers. Results confirmed that SMEs UK retailers are facing both entry and growth stage problems during international expansion. Fornes and Cardosa (2019) [143] provided deep insights on the barriers faced by SMEs from emerging economies when doing business abroad and, especially, to discriminate among its different sources of liabilities. The study focused on few main areas: limited knowledge of external markets, socio-cultural differences, unfamiliarity with different contexts and business practices, and limited local business contacts, reliable representatives, and control systems.
In summary, the literature that focuses on this area highlights a variety of internationalisation barriers for the international integration phase. The barriers were classified into four categories: socio-political barriers (e.g., institutional and political), environmental barriers (e.g., uncertainty and dissimilarity), market barriers and barriers related to resources (e.g., technology, and human resources).
Ultimately, the authors who have done work on the internationalisation barriers for the international integration phase analysed all the varieties of internationalisation barriers: socio-political barriers, environmental barriers, market barriers, barriers related to resources. It follows, therefore, exhaustive literature about this area. We present in Table 12 a classification of the topics covered by the work of the authors examined.

Barriers References
Market [140,[142][143][144] Resources [139,145] Environmental [129,145] Socio-political [129,139,141,143] Area 10: Impact of international extension on performance The tenth area includes 3 papers and focuses on the impact of international extension on performance. Following is a description of the study objective, the methodology used, and the results obtained. Kauppinen et al. (2012) [146] presented a cycle of learning to investigate the internationalisation of SMEs. Researchers stated that among the various stages of the learning cycle, the initial stage is more significant as compared to other stages. Thus, internationalisation occurs as a by-product of social action. Jin and Hurd (2019) [147] explored how digital platforms impact New Zealand SMEs companies' entry into the Chinese market. The obtained results suggested that digital platforms ease entry barriers to some extent, particularly in helping overcome resource constraints and facilitating access to network.
In summary, the literature that focuses on this area highlights a variety of performances for the international extension phase. These performances were classified into four categories: economic-financial performances (e.g., profits, sales, and costs), technical performances (innovation, and growth of specific skills), market performances (e.g., market share, market flexibility, and reputation), and organisational performances (e.g., relationships, partnerships, and organisational agility).
Ultimately, the author who has done work/worked on the performance in the extension phase analysed the organisational and technical performances. We considered inappropriate discussion of the economic-financial and market performance. The literature is, therefore, exhaustive. A summary overview of the topic examined by the authors, as presented in Table 13. Table 13. Impact of international extension on performance.

Performance References
Economic-financial -

Market -
Technical [146,147] Organisational [146,148] Area 11: Impact of international penetration on performance The eleventh area also includes 3 papers and focuses on the impact of international penetration on performance. Following is a description of the study objective, the methodology used, and the results obtained.
De Noni et al. (2015) [149] used a path regression model to investigate how exploitative and exploratory learning can moderate the SMEs' exporting process to foster firm performance. The analysis summarized that exploitation does not affect small firms' internationalisation performance, but it is possibly a critical antecedent to effectively move towards internationalized markets, whereas, exploration significantly and positively leverages the impact of international involvement on firm performance. Saeed and Ziaulhaq (2019) [150] analysed the role of chief executive officers characteristics like age, education, tenure, and political connectedness affected SMEs' international performance.
In summary, the literature that focuses on this area highlights a variety of performances for the early entrance/development phase. These performances were classified into 4 categories: economic-financial performances (e.g., profits, sales and costs), technical performances (e.g., innovation, and growth of specific skills), market performances (e.g., market share, market flexibility, and reputation), and organisational performances (e.g., relationships, partnerships and organisational agility).
Ultimately, the author who has done work on the performance's international penetration phase analysed the organisational and market performances. There is a gap regarding the treatment of the technical and economic-financial performance in the penetration phase. We proposed in Table 14 a summary overview of the topic by the author's work examined. Table 14. Impact of international penetration on performance.

Performance References
Economic-financial -Market [149] Technical -Organisational [149][150][151] Area 12: Impact of international integration on performance The twelfth area includes 28 papers and focuses on the impact of international integration on performance. Following is a description of the object of the author's analysis, the methodology used, and the results obtained. Jin et al. (2016) [152] investigated the impact of personal networks and business networks on SMEs post international market entry performance. A total of 105 mail survey responses gathered from U.S. SMEs were analysed using multiple regression methods. Hypotheses testing supported that business networks enhanced foreign market knowledge which further improved SMEs' international performance. While personal networks somewhat assist SMEs in attaining knowledge of foreign markets and international performance.
Torkkeli et al. (2016) [153] examined how network competence affects SMEs' national and international growth. For this, data were collected from 298 Finnish SMEs, representing five different industries, and analysed using regression. Results reported network expertise as a significant predictor of the SMEs' growth while operating internationally. Prasanthi et al. (2016) [154] studied how the process of internationalisation affects the company's performance. Considering the theoretical approach, the authors advocated that an emphasis on R&D and marketing capabilities in the internationalized marketplace can positively foster SMEs' innovations. Jeong et al. (2016) [155] investigated which types of international networks affect SMEs' internationalisation performance. For this, data collected from 484 exporting Korean SMEs were analysed employing multiple regression analysis. Findings galvanized that business networks with customers improve SMEs' financial and strategic performance in international markets. Analysing the case study of a Chinese SMEs, He et al. (2016) [156] claimed/showed that SMEs in emerging economies become more proactive in international growth during the institutional transition. Lee et al. (2012) [157] explored the impact of sales internationalisation with the direct and moderating impact of technology resources and R&D alliances on SMEs. A total of 1612 Korean companies SMEs was surveyed, and logistic regression was used, which claimed that sales internationalisation is positively related to SMEs' better survival. Likewise, R&D plays the role of a moderator; and technology resources do not provide direct benefits in the SMEs' international survival. Sommer (2009) [158] explored the role of SMEs owners/managers in their firms' internationalisation. In doing so, stepwise regression was used for hypothesis testing, which stressed that both personal experiences and positive attitude towards the risk of the SMEs owners/managers enhance the chances of active participation in the internationalisation process. Pett et al. (2009) [159] highlighted the importance of internationalisation and innovation for SMEs' growth. Findings suggested that both internationalisation and innovation lead towards significant product and process improvements, whereas internationalisation, environmental uncertainty, and product improvement significantly lead to superior performance. O'Cass et al. (2009) [160] surveyed 302 SMEs managers using a questionnaire and highlighted that international SMEs differ in terms of international entrepreneurship, innovation intensity and firm size in comparison with non-international SMEs. Due to product differentiation, low production costs and adoption of concentration strategies, international SMEs are in higher demand. Nummela et al. (2006) [161] interviewed CEOs of SMEs to illustrate and analyse the change in the internationalisation process in three internationalizing Irish SMEs. The study demonstrated that the internationalisation process has led to a series of positive changes that are reflected in the growth of corporate performance. Le Roy et al. (2008) [162] studied the impact of internationalisation on the SMEs' competitive strategies. The analysis of 59 SMEs has shown a significant difference between international and regional SMEs in competitive dimensions. Due to product differentiation, low production costs and adoption of concentration strategies, international SMEs are in higher demand. Trudgen et al. (2014) [163] highlighted the importance of effective performance measures in the globalized marketplace by analysing multiple case studies. Results reported that the development of relevant performance measures according to the firms' characteristics and strategies could significantly improve international performance. Pinho et al. (2018) examined whether international readiness, including innovation, competition, technology-orientation and opportunity perception impact on internationalisation of small businesses differently in Asian countries compared to the complete Global Entrepreneurship Monitor sample [164]. Bianchi et al. (2017) [165] analysed managerial and technology-related capabilities and their impact on international performance SMEs drawing on data from 233 Chilean SMEs, developed and tested a model using structural equation modelling. The study showed that international entrepreneurial opportunity recognition and international networks mediate the relationship between international entrepreneurial orientation and internet technology capabilities on SMEs' international performance.
In summary, the literature that focuses on this area highlights a variety of performances for the international integration phase. The performances were classified into four categories: economic-financial performances (e.g., profits, sales and costs), technical performances (e.g., innovation and growth of specific skills), market performances (e.g., market share, market flexibility and reputation), and organisational performances (e.g., relationships, partnerships and organisational agility).
Ultimately, the authors who have done work on the performance in the integration phase analysed the organisational, technical economic-financial and market performances. It follows, therefore, exhaustive literature about this area. We proposed in Table 15 a summary overview of the topics covered by the work of the authors examined. Table 15. Impact of international integration on performance.

Conclusions
In this paper, we discussed the factors affecting SMEs in the internationalisation process. A systematic literature review was conducted to provide an in-depth understanding of SMEs internationalisation and to highlight the existing research gaps. The review process consisted of two main phases: papers' selection and content analysis. The Scopus and Web of Science databases were adopted, and a total of 161 papers were selected for the subsequent analyses. The analysis of the previous contributions allows us to identify four topic areas (i.e., factors influencing internationalisation, internationalisation models, internationalisation barriers and the impact of internationalisation on performance). Further, the papers were analysed based on the phases of the internationalisation process (i.e., extension, penetration, and integration), the intersection between the topic areas and the phases of the internationalisation process enabled authors to identify and underline 12 content areas (Section 3). The analysis of the 12 different areas identified has shown several lacks in the body of literature and enabled us to formulate seven research questions. Notably, four research gaps were identified. The first gap was found in models and theories formulated for Internalisation Growth/ Consolidation (Area 6). The second gap is associated with barriers and obstacles related to the early stage of Early Entrance/Development (Area 8). There is no discussion on the barriers related to resources such as technology, human resources, and materials. The third gap is concerned with Area 1 concerning the performance to the phase of input Early Entrance / Development. The gap is related to the discussion of technical performance (e.g., innovation, and growth in specific skills) and the economic-financial performance (e.g., profits, sales growth, cost reduction) Concerning the stage of the process in question. The fourth gap is associated with the impact of internationalisation on performance during Internalisation Growth/Consolidation (Area 12). There is no debate on the impact of international supply chain disturbances that jeopardizes performance on international markets and calls for resilience. Table 16 presents the research questions associated with each research gap identified.
Finally, this study is not without limitations, some of which can be addressed by future research. This review provides an overview of the topic investigated, but does not deploy an analytical framework and does not generate detailed hypotheses for empirical analysis. Also, the criteria adopted in the review protocol may exclude a few important related papers on SMEs internationalisation. Therefore, limitations of the presented study arise from the subjectivity of the content analysis method, from the background of involved researchers. RQ6 What are key resilience strategies to minimize the impact of international supply chain disturbances?
RQ7. How can firm effectively measure and improve its supply chain resilience in international markets?
Finally, the review conducted in this paper is based on a systematic review approach; therefore, an interesting research direction to be further investigated relates to the adoption of a different review methodology. Specifically, a bibliometric analysis of the literature or additional statistical analysis can be used to triangulate or complement the results achieved in this paper.