Past Trends and Future Directions in Green Human Resource Management and Green Innovation: A Bibliometric Analysis

: Global environmental concerns have prompted organizations to adopt green human resource management practices that will eventually lead to green innovations. Given that understanding, this study aims to converge multidimensional research published on green human resource management (GHRM) and green innovation. In addition, it seeks to discuss the topic’s research trends in the context of what, how, when, where, and by whom. The data were retrieved from the Scopus database (until March 2023), and VOSviewer was used to investigate the research trends. A total of 312 documents were extracted from the Scopus database, and 46 published articles were finalized using the PRISMA flow approach. The results indicate that there has been an upward trend in terms of published articles on the topic, and the highest number of articles (15) were published in the current year, 2023. The co-occurrence results indicate that GHRM is strongly associated with environmental performance and green innovation. The journals Environmental Science and Pollution Research and Sustainability (Switzerland) stand out in this domain. The Abu Dhabi University of United Arab Emirates is the most cited institution, whereas Saudi Arabia has the highest co-authorship at the country level. Furthermore, this study summarizes the major developments in this research domain and suggests research gaps and possible future directions.


Introduction
At present, organizations are concerned about environmental challenges and seeking sustainable resources for business development.Sustainable resources not only provide a competitive edge to organizations but are also linked to social and societal well-being [1].The increased pressure from society and external stakeholders has led organizations to opt for green human resource management (GHRM) as a strategic tool to achieve sustainable goals in the long run [2].Studies show that GHRM has a positive impact on the green behavioral outcomes of employees, which ultimately lead toward better environmental, social, financial, and innovation performance [3].As a result, GHRM reflects an organization's strategic focus on environmental preservation and enables top decision-makers to pay attention to practices that encourage individuals to engage in green activities in order to lessen the environmental harm [4].Consequently, green human resource management practices are becoming important for organizations to be sustainable and competitive in the market [5].
Green human resource management refers to the use of HRM practices to support environmental sustainability goals within the organization; green HRM practices cover the Sustainability 2024, 16, 133 2 of 20 aspects of green recruitment and selection, training and development, rewards and compensation, and performance management systems [6].These mentioned aspects of GHRM motivate employees to participate in activities related to the sustainable development of the organization [7].Such green activities will help the organization obtain an attractive green image with enhanced environmental performance [8].By indulging in such green activities through the implementation of GHRM, employees will be able to come up with creative solutions to environment-related issues, leading to green innovations.
Past studies have highlighted the relationship between GHRM and green innovation.Organizations that implement GHRM practices are better able to innovate products and processes that cause the least harm to the environment [9][10][11].Green innovation refers to creative ideas for developing eco-friendly products and processes by adopting green activities, using eco-friendly raw materials, aiming at environmentally friendly policies that can reduce harmful environmental emissions, and reducing the use of resources (electricity, water, gas, fuels, and other raw materials) [12].
Green hiring recruits employees who are concerned with environmental issues and have the required knowledge and competencies to solve environment-related issues [11].Likewise, green training enables employees to acquire the required knowledge, skills, and competencies for green innovation.As a result, they come forward with novel ideas to innovate products and processes that are eco-friendly [13].Studies suggest that organizations focusing on green innovations are better able to achieve enhanced environmental and organizational performance in the long run [14].Green innovation has now become a significant strategic tool for organizations and might be portrayed as a blend of information and abilities to develop products and services with the least harm to the environment [15].
Carbon emissions, global warming, and climate change are currently the most topical issues all over the world, and businesses are adopting modern and innovative solutions [16].Organizations are now examining the role of GHRM in bringing green innovation to reduce carbon footprints and other hazardous emissions that are detrimental to the environment [17].Organizations are keen to devote more resources to research on new technologies to mitigate the effects of environmental degradation by developing products that are less harmful to the ecosystem [18].
In light of the above discussion, past studies have proven the positive role of GHRM in bringing these innovations related to sustainability [19][20][21].In this regard, this study applies a bibliometric approach to investigate the relationship between GHRM and green innovation in the published literature.The main objective of this study is to map the historical trends that serve as a foundation for building future research agendas for researchers and policymakers.It aids in identifying significant research gaps, which can be crucial for further investigation.In the past, researchers have applied a bibliometric analysis to GHRM, but there exists a research gap in investigating the trends between GHRM and green innovation.This study aims to answer the following questions using the bibliometric approach: 1.
What are the past and current trends in the published literature on GHRM and green innovation regarding different journals, citations, geographical distribution, authorship, and bibliographic coupling analysis?2.
What are the identified research gaps in the respective domains determined through co-occurrence analysis of keywords?
The answers to the above questions are important for providing an overview of the past, present, and future research on the topic of GHRM and its impact on green innovations.Further, they will enable researchers to develop a comprehension of all of the major developments in the research domain and identify possible research gaps for future studies.Moreover, researchers can follow the work of leading scholars, focus on top journals, and link the keywords/variables to address research gaps.Bibliometric analysis highlights the research-knowledge bases during various time stages, research hotspots and specifically inter-disciplinary research domains.This study contributes in several ways; firstly, the study summarized the contributions of different authors, countries, institutions, and journals on publishing the literature on the given topic through different analyses, i.e., citation, co-authorship, institutional reference, geographical distribution, and yearly journal publication trends.Secondly, the keywords analysis serves as a source of gap identification for future researchers.A high frequency of keywords depicts the current trends in the literature, whereas a low frequency of keywords shows the potential for future investigation.Thirdly, the citation analysis of articles, institutions, and documents helps scholars to identify the impact of highly cited articles.The commonly cited publications also reflect the study field's mainstream and serve as the knowledge base for future research.Further, the trends in the topic of driving green innovations through GHRM will help scholars include various analytical perspectives combined with scientific knowledge in their research, which will serve as a base for organizational decision makers.Lastly, the bibliographic coupling analysis will guide future researchers regarding the strong inter-and intra-connectivity of the groups to interpret which topics and research trends are mostly referred to.The dominance of the cluster emphasizes the importance of current research trends being followed in the given domain, and the connectivity of the topics or ideas will help readers to assess the similarity between the articles.

Materials and Methods
To conduct bibliometric analysis, the study relies on (1) the Scopus database for data retrieval, (2) the PRISMA approach for data screening and (3) Vosviewer software version 1.6.18for performing the analyses.

Database for Retrieving Articles
Data were extracted from Scopus, a well-reputed database known for quality journals.According to Gaurav et al. [22], Scopus is a profoundly solid database as it covers a broad scope of distributed material in different spaces.Moreover, it provides extensive details of authors, references, authors, affiliations, journals, countries, years of distribution, and so forth, which empowers us to perform bibliometric examination [23].
Certain keywords were entered to obtain the desired data for analysis.The criteria for searching different articles play a crucial role in data extraction.As this paper is intended to investigate the relationship trends between GHRM and green innovation, the following search string was applied:

•
Scopus TITLE-ABS-KEY ((Green AND Human AND Resource AND Management) AND (Green AND Innovation)) Data Extraction date 10 April 2023.These keywords helped in the extraction of 312 documents altogether from 2014 to 2023.Although the term GHRM was present in the literature before the year 2014, and a few studies even highlighted its positive organizational outcomes [6], there is no prior literature available on GHRM leading to green innovation.A large portion of them were published articles alongside conference papers, review papers, and book chapters, and the rest were blanks.

Technique Used for Filtering out Data
The PRISMA approach is widely recommended for the screening process of the data.It consists of 3 steps as described in Figure 1: identification, screening of data for exclusion and lastly the inclusion of the final material required for the review.In the first step, identification, the Scopus database provided 312 articles in total.At this stage, before screening, 5 articles were removed, as the file had some blanks in it, which could lead to misinformation in the future.Based on the search query, the Scopus database provided data of articles including the query keywords anywhere in the title and abstract.It is imperative that keywords should be used in the intended context.Therefore, in the second step, 258 records were eliminated after careful reading of the titles and abstracts.For screening purposes, we particularly referred to GHRM as the "Set of policies and practices aimed towards achieving green organizational objectives and developing green employee behaviour" [3].Accordingly, green innovation is referred to as the "Development of new products and processes which reduce environmental impact" [21].We retrieved a total of 49 articles that addressed the relation between GHRM and green innovation.We selected only those articles in which GHRM was linked with green innovations or HRM practices (recruitment, selection, hiring, training, performance appraisals) or had some linkage with the sustainability domain and led to green innovations.Out of these 49 retrieved articles, three were further removed, as one of them was a conference paper and the remaining two were review papers.At the final stage, 46 published articles were selected for analysis.There are no set guidelines available for the sample sufficiency criteria; however, past studies have shown that even a sample size of less than 50 articles is acceptable in bibliometric analysis [24,25].The PRISMA approach helps researchers to eliminate irrelevant information so that the findings provide focused insights.Thus, the sample size of this study was sufficient for the bibliometric analysis Sustainability 2023, 15, x FOR PEER REVIEW records were eliminated after careful reading of the titles and abstracts.For screenin poses, we particularly referred to GHRM as the "Set of policies and practices aim wards achieving green organizational objectives and developing green employee iour" [3].Accordingly, green innovation is referred to as the "Development of new ucts and processes which reduce environmental impact" [21].We retrieved a tota articles that addressed the relation between GHRM and green innovation.We s only those articles in which GHRM was linked with green innovations or HRM pr (recruitment, selection, hiring, training, performance appraisals) or had some linkag the sustainability domain and led to green innovations.Out of these 49 retrieved a three were further removed, as one of them was a conference paper and the rem two were review papers.At the final stage, 46 published articles were selected for an There are no set guidelines available for the sample sufficiency criteria; howeve studies have shown that even a sample size of less than 50 articles is acceptable in metric analysis [24,25].The PRISMA approach helps researchers to eliminate irre information so that the findings provide focused insights.Thus, the sample size study was sufficient for the bibliometric analysis

Software Used for Analysis
VOSviewer software (version 1.6.18)was used to run the bibliographic analysis.This software was selected because of its user-friendly interface and attractive visual representa-tion of the results.It helps to run different analyses, to know the impactful authors, number of citations, major countries contributing in the given domain, major institutes working in this field, bibliographic coupling analysis, and major documents co-authored.The network images help us to better understand the trends and analysis by showing links among items.Additionally, VOSviewer can better examine the bibliographic pointers more efficiently.

Yearly Publication and Citation Trends
Figure 2 shows the yearly publication trends for articles extracted from the Scopus Database.The graph is somewhat linear, with small variations from 2014 to 2019; however, from 2020 to March 2023, it shows a rapid increase in the number of publications.

Software Used for Analysis
VOSviewer software (version 1.6.18)was used to run the bibliographic analysis.This software was selected because of its user-friendly interface and attractive visual representation of the results.It helps to run different analyses, to know the impactful authors, number of citations, major countries contributing in the given domain, major institutes working in this field, bibliographic coupling analysis, and major documents co-authored.The network images help us to better understand the trends and analysis by showing links among items.Additionally, VOSviewer can better examine the bibliographic pointers more efficiently.

Yearly Publication and Citation Trends
Figure 2 shows the yearly publication trends for articles extracted from the Scopus Database.The graph is somewhat linear, with small variations from 2014 to 2019; however, from 2020 to March 2023, it shows a rapid increase in the number of publications.Out of these 46 published articles, 15 were published in 2023, which is the highest number of publications in a year.Table 1 shows the yearly citation trend; it can be seen that articles published in the year 2020 received the highest number of citations (n = 705).Although the maximum number of articles were published in 2023, they have not yet received the maximum number of citations.Out of these 46 published articles, 15 were published in 2023, which is the highest number of publications in a year.Table 1 shows the yearly citation trend; it can be seen that articles published in the year 2020 received the highest number of citations (n = 705).Although the maximum number of articles were published in 2023, they have not yet received the maximum number of citations.

Journal Publication Trends
Table 2 shows that a total of 44.68% of the reviewed articles on the topic of GHRM and green innovation were concentrated in 10 journals.Of these 10 journals, ''Environmental science and Pollution Research" and ''Sustainability (Switzerland)" topped the table with the maximum number of publications (n = 4), with 8.51% on the linkage between GHRM and green innovation.Green innovation comes under the domain of sustainability, which is one of the core areas of these two journals.Furthermore, GHRM is linked with many desirable organizational outcomes (i.e., organizational and environmental performance); thus, this topic is gaining the attention of these academic journals.Table 2 lists the main journals in terms of number of publications and citations.Along with this information, the impact factor of the journals is also mentioned in the table.Journals with a greater number of publications may not have high impact factors.The journal with the highest impact factor (11.072) was the ''Journal of Cleaner Production", although its publications were fewer in number.Another journal, ''Research Policy", stood out with an impact factor of 9.473 but has only one publication to date.
In this selected list of journals, the total number of citations received by journals publishing articles on GHRM in relation to green innovation is also mentioned.The journal "Technological Forecasting and Social Change" received the highest number of citations, 1073, followed by the journal "Research Policy", which received 158 citations.The article published in the journal "Technological Forecasting and Social Change" with the highest number of citations (n = 509) discusses the impact of green transformational leadership on GHRM, which further enhances green innovation [9].Another article with the highest number of citations (n = 85) published in the "Journal of Cleaner Production" with maximum impact factor discusses how some of the activities of GHRM such as green training, green compensation, and green recruitment will affect green team creativity, leading to green product innovation [26].The most highly cited documents published in their respective journals are also listed in the above Table.

Citation Analysis
Citation analysis refers to the number of times a particular institute, document, country, or author has received citations [27].Using the software VOSviewer, different citation analyses were conducted with different units of analysis to determine the citation impact of a particular institute, author, document, or country.

Institutional Analysis
Citation analysis was performed by keeping 'institution' as the unit of analysis.This analysis helped us to interpret which educational institution is the most impactful in receiving the maximum number of citations.The criteria for the analysis were set up as the minimum number of documents per institution (n = 1) so that a maximum number of institutes could meet the threshold.
"Abu Dhabi University of United Arab Emirates" tops Table 3 with the maximum number of citations (n = 921), and it is the only institute that has published two articles thus far on the given topic.The article that was published first with reference to Abu Dhabi University has received 412 citations, and it discusses the drivers of green innovation that are necessary for the competitive advantage of a company.One of the drivers of green innovation discussed in the paper is HR practices [28].The Paris School of Business, France; National Research University, Russia; and University of Milano, Italy collaborated in publishing an article in 2020 that stands out with 509 citations and discusses the mediation of green innovation between GHRM and environmental performance [9].Table 3 summarizes the top 12 institutes with the maximum number of citations received on published articles along with the individual article citations.

Document Analysis
After running citation analysis on VOSviewer by keeping 'documents' as the unit of analysis and selecting the minimum number of citations per document (n = 5), the results showed that 24 out of 46 documents met the threshold.Figure 3, extracted from VOSviewer, shows different clusters.The size of the cluster shows the dominance of the article by author with respect to received citations.Figure 3 shows that the article by Singh et al. [9] dominated, as it was interlinked to different authors and received the highest number of citations (n = 509).Table 4 further elaborates on the documents alongside their citations, authors, and year of publication.The top 10 documents with the maximum number of citations were selected.An article with a notable number of citations (n = 114) discusses the mediation effect of GHRM between green transformational leadership and green creativity.The variable of green creativity was discussed while keeping in mind the concept of innovativeness [29].Lastly, the document with the smallest number of citations (n = 36) by Bossle et al. [30] discussed the green innovation in food companies and how they can opt for eco-friendly innovation based on important internal and external factors.One of the major internal factors discussed was HRM practices, which led to eco-innovation in the food industry of Brazil.
University of New Mexico, United States

Document Analysis
After running citation analysis on VOSviewer by keeping 'documents' as the unit of analysis and selecting the minimum number of citations per document (n = 5), the results showed that 24 out of 46 documents met the threshold.Figure 3, extracted from VOSviewer, shows different clusters.The size of the cluster shows the dominance of the article by author with respect to received citations.Figure 3 shows that the article by Singh et al. [9] dominated, as it was interlinked to different authors and received the highest number of citations (n = 509).Table 4 further elaborates on the documents alongside their citations, authors, and year of publication.The top 10 documents with the maximum number of citations were selected.An article with a notable number of citations (n = 114) discusses the mediation effect of GHRM between green transformational leadership and green creativity.The variable of green creativity was discussed while keeping in mind the concept of innovativeness [29].Lastly, the document with the smallest number of citations (n = 36) by Bossle et al. [30] discussed the green innovation in food companies and how they can opt for ecofriendly innovation based on important internal and external factors.One of the major internal factors discussed was HRM practices, which led to eco-innovation in the food industry of Brazil.

Document
TC Author Yea r "Green innovation and environmental performance: The role of green transformational leadership and green human resource management" 509 Singh et al. [9] 2020 "Green innovation and organizational performance: The influence of big data and the moderating role of management commitment and HR practices" 412 EI-Kassar and Singh [28] 2019 "Analyzing the relationship between green innovation and environmental performance in large manufacturing firms" 152 Rehman et al [21] 2021 "The continuous mediating effects of GHRM on employees' green passion via transformational leadership and green creativity" 114 Jia et al. [29] 2018 "Technological turbulence and greening of team creativity, product innovation, and human resource management: Implications for sustainability" 85 Ogbeibu et al.

Authors' Analysis
A citation analysis on the author level was performed, and the results showed that 54 out of 174 authors met the threshold after keeping the criteria as the minimum number of documents per author (n = 1) and number of citations per author (n = 10).
Figure 4 shows dominant clusters of impactful authors receiving the maximum number of citations for articles published on GHRM and green innovation.Singh S.K. is prominent in the figure, with two documents and the highest number of citations (n = 921).The respective articles provided insights about the significant role of green transformational leadership in enhancing environmental performance through the mediating role of green innovation.The second article highlighted the mediating role of HR practices between green innovation and organizational performance.GHRM plays a vital role in enhancing eco-friendly innovation, which leads to sustainable firm performance [9] Further, Table 5 maps out the top 10 authors with the maximum number of citations (TC), total number of documents by author (TN), and their most highly cited document.A study analyzed a complex model involving GHRM, green intellectual capital, green innovation, and environmental strategies, and the outcome variable was environmental performance [21].The results for the given article show that GHRM and green intellectual capital lead to green innovation, which further enhances the green performance of the organization.Environmental strategies act as a moderator variable and strengthen the relationship between green innovation and environmental performance.The rest of the authors with their citations are listed in Table 5.
"Effects of green human resource management and managerial environmental concern on green innovation" 53 Song et al. [11] 2020 "Enhancing the FIRM'S green performance through green HRM: The moderating role of green innovation culture" 43 Muisyo and Qin [32] 2021 "Why food companies go green?The determinant factors to adopt eco-innovations" 36 Bossle et al. [30] 2016

Authors' Analysis
A citation analysis on the author level was performed, and the results showed that 54 out of 174 authors met the threshold after keeping the criteria as the minimum number of documents per author (n = 1) and number of citations per author (n = 10).
Figure 4 shows dominant clusters of impactful authors receiving the maximum number of citations for articles published on GHRM and green innovation.Singh S.K. is prominent in the figure, with two documents and the highest number of citations (n = 921).The respective articles provided insights about the significant role of green transformational leadership in enhancing environmental performance through the mediating role of green innovation.The second article highlighted the mediating role of HR practices between green innovation and organizational performance.GHRM plays a vital role in enhancing eco-friendly innovation, which leads to sustainable firm performance [9] Further, Table 5 maps out the top 10 authors with the maximum number of citations (TC), total number of documents by author (TN), and their most highly cited document.A study analyzed a complex model involving GHRM, green intellectual capital, green innovation, and environmental strategies, and the outcome variable was environmental performance [21].The results for the given article show that GHRM and green intellectual capital lead to green innovation, which further enhances the green performance of the organization.Environmental strategies act as a moderator variable and strengthen the relationship between green innovation and environmental performance.The rest of the authors with their citations are listed in Table 5.    Citation analysis highlighted the substantial work achieved in the domain of GHRM and green innovation literature.The number of citations assisted us in identifying key articles that received recognition from other scholars working in the respective domains.Articles from Abu-Dhabi university that received the highest number of citations discussed green transformational leadership and environmental performance, along with GHRM and green innovation.Scholars who aspire to work in this domain could consider these highly cited articles to comprehend major developments and further build on provided guidelines in these articles."Green innovation and environmental performance: The role of green transformational leadership and green human resource management" "Green innovation and organizational performance: The influence of big data and the role of management commitment and HR practices" Chierici R. Giudice M.D. Graziano D. [9] 509 1 "Green innovation and environmental performance: The role of green transformational leadership and green human resource management" EI-Kassar.[28] 412 1 "Green innovation and organizational performance: The influence of big data and the moderating role of management commitment and HR practices" Antonioli D. Mancinelli S. Mazzanti M. [33] 158 1 "Is environmental innovation embedded within high-performance organisational changes? the role of human resource management and complementarity in green business strategies" Rehman S.U.Kraus S. [21] 152 1 Analyzing the relationship between green innovation and environmental performance in large manufacturing firms

Co-Authorship Analysis
Co-authorship analysis tells us about how a particular document has been produced by two or more authors [34].This type of analysis reveals the linkage of authors on the basis of the number of articles produced by the particular authors [23].Using the software VOSviewer, this analysis can be run at the level of authors, organizations, and countries.

Co-Authorship at Country Level
Using the software VOSviewer, co-authorship analysis at the country level was performed to identify the collaboration of authors across different countries.Co-authorship at the country level will help us to understand how a particular document has been coauthored from different origins, with some major countries showing collaboration on publishing articles on green innovation induced by GHRM.By keeping ''Countries" as the unit of analysis and setting a minimum number of documents per author (n = 2) and minimum number of citations per author (n = 5), the results obtained after running coauthorship analysis show that 13 out of 32 countries met the threshold, illustrating the collaboration of authors in bringing out documents on GHRM and green innovation.The criteria set for the given analysis resulted in Figure 5, as extracted from VOSviewer.
Chierici R. Giudice M.D. Graziano D. [9] 509 1 "Green innovation and environmental performance: The role of green transformational leadership and green human resource management" EI-Kassar.[28] 412 1 "Green innovation and organizational performance: The influence of big data and the moderating role of management commitment and HR practices" Antonioli D. Mancinelli S. Mazzanti M. [33] 158 1 "Is environmental innovation embedded within high-performance organisational changes? the role of human resource management and complementarity in green business strategies" Rehman S.U.Kraus S. [21] 152 1 Analyzing the relationship between green innovation and environmental performance in large manufacturing firms Citation analysis highlighted the substantial work achieved in the domain of GHRM and green innovation literature.The number of citations assisted us in identifying key articles that received recognition from other scholars working in the respective domains.Articles from Abu-Dhabi university that received the highest number of citations discussed green transformational leadership and environmental performance, along with GHRM and green innovation.Scholars who aspire to work in this domain could consider these highly cited articles to comprehend major developments and further build on provided guidelines in these articles.

Co-Authorship Analysis
Co-authorship analysis tells us about how a particular document has been produced by two or more authors [34].This type of analysis reveals the linkage of authors on the basis of the number of articles produced by the particular authors [23].Using the software VOSviewer, this analysis can be run at the level of authors, organizations, and countries.

Co-Authorship at Country Level
Using the software VOSviewer, co-authorship analysis at the country level was performed to identify the collaboration of authors across different countries.Co-authorship at the country level will help us to understand how a particular document has been coauthored from different origins, with some major countries showing collaboration on publishing articles on green innovation induced by GHRM.By keeping ''Countries'' as the unit of analysis and setting a minimum number of documents per author (n = 2) and minimum number of citations per author (n = 5), the results obtained after running co-authorship analysis show that 13 out of 32 countries met the threshold, illustrating the collaboration of authors in bringing out documents on GHRM and green innovation.The criteria set for the given analysis resulted in Figure 5, as extracted from VOSviewer.As shown in the figure, Saudi Arabia dominated in this regard with the highest number of co-authorship links (n = 7) with different countries, followed by Pakistan with the second highest number of co-authorship links (n = 6).Countries with similar colors represent those that are geographically close.
For a better understanding of the above figure, a table was extracted to show the documents co-authored by the respective countries, the total number of joint links by the countries, and lastly, the number of citations the countries have received on co-authored articles.Table 6 shows that although Pakistan had the highest number of co-authored documents (n = 15), it had fewer collaborative links (n = 6) than Saudi Arabia (n = 7).Saudi Arabia stood out in collaborative links but came third on the number of documents (n = 9).Lastly, with regard to the number of citations, Italy dominated the table with n = 819 citations, followed by France (n = 535), China (n = 251), the United States (n = 237) and Pakistan (n = 209).Co-authorship analysis at the country level reflects significant collaborative research patterns among different countries.It also highlights the prevailing research networks within each country.Policymakers and research-funding institutes consider this analysis for investments and research grants.Future research grants can be invested in countries with high collaboration links, as they attract more international collaboration.Saudi Arabia and Pakistan have strong collaborative networks and potential for future research studies in this domain.

Bibliographic Coupling Analysis of Documents
Bibliographic coupling analysis of documents tells us about a third common document being referred by two or more articles.Documents are considered to share the same cluster or group if they have a greater number of overlapping references [25].Figure 6 was extracted by running a bibliographic coupling analysis.The results show that 26 out of 46 documents met the given criteria.The results were obtained by keeping the minimum number of citations per document set at n = 3, which resulted in four clusters and 26 items.Figure 6 shows four dominant colors: red, yellow, blue and green.The generated clusters could be named Cluster 1 (red group), Cluster 2 (green group), Cluster 3 (blue group), and Cluster 4 (yellow group) for better comprehension.
The inter-and intra-connections of references between or within groups can be interpreted from Figure 6.Discussing the red group, one of the articles addresses detriments of GHRM using the ability, motivation and opportunity (AMO) concept, which helps in process innovation in the manufacturing industry of Malaysia [35].This article is further cited by two other documents in the same group.One of them treats innovation capacities as a mediator between GHRM and competitive advantage [36], and the other one addresses the role of green product innovation as a mediator between GHRM and green supply chain management [37].Talking about the interconnections of the groups, one of the articles in the green group is cited by two articles in the yellow group.Another article addresses the intention of small business to pursue eco-innovation through practices of GHRM in the organization [38], and the other article in the same group talks about the impact of GHRM and green intellectual capital on environmental performance, with green innovation as a mediator [39].Both of these documents referred to a common article published in 2020.This article addresses two factors, i.e., GHRM and the concern of management towards the environment, which help in stimulating green innovation [11].So, the following figure summarizes the bibliographic coupling of documents that share common references.
in comprehending the major patterns and themes that are frequently cited.The graph clearly illustrates that one of the documents in the blue group has the most references and discusses the impact of green transformational leadership on GHRM, hence promoting green innovation [9].Another article with a sufficiently large cluster size addresses the role of GHRM in mediating the relationship between big data and green innovation [28].As a result, both of these documents are highly cited.

Co-Occurrence: Authors' Keywords Analysis
Using Vosviewer, co-occurrence analysis was run to know how many times authors' keywords co-occurred with each other.Co-occurrence analysis helps us to dig into the latest research areas and also identifies the gaps for future research contributions [25].The keywords used fewer times serve as a gap analysis for future purposes.Figure 7 shows that 28 out of 156 keywords met the given threshold after setting the criteria as minimum number of occurrences of a keyword as n = 2.The figure elaborates that different keywords used by authors have contributed in linking GHRM and green innovation, such as Eco-Innovation, Environmental Performance, Green Innovation, Organizational Performance, Green Human Capital, Green Product Innovation, Training, Corporate Social Responsibility, Green Creativity, Management Commitment, etc. Bibliographic coupling analysis enables us to comprehend the key papers that share a substantial number of references.Moreover, the size of the clusters demonstrates the strength of the relationship between documents based on shared references.It assists us in comprehending the major patterns and themes that are frequently cited.The graph clearly illustrates that one of the documents in the blue group has the most references and discusses the impact of green transformational leadership on GHRM, hence promoting green innovation [9].Another article with a sufficiently large cluster size addresses the role of GHRM in mediating the relationship between big data and green innovation [28].As a result, both of these documents are highly cited.

Co-Occurrence: Authors' Keywords Analysis
Using Vosviewer, co-occurrence analysis was run to know how many times authors' keywords co-occurred with each other.Co-occurrence analysis helps us to dig into the latest research areas and also identifies the gaps for future research contributions [25].The keywords used fewer times serve as a gap analysis for future purposes.Figure 7 shows that 28 out of 156 keywords met the given threshold after setting the criteria as minimum number of occurrences of a keyword as n = 2.The figure elaborates that different keywords used by authors have contributed in linking GHRM and green innovation, such as Eco-Innovation, Environmental Performance, Green Innovation, Organizational Performance, Green Human Capital, Green Product Innovation, Training, Corporate Social Responsibility, Green Creativity, Management Commitment, etc.
Table 7 includes the top 20 keywords on the basis of the maximum number of cooccurrences.Green Innovation occurred the highest number of times (n = 18), forming a maximum number of links with other keywords.The average publication year for Green Innovation was 2021.Next came Green Human Resource Management, which occurred 16 times, with an average of 16 links being publicized in 2020.The occurrences of some other keywords are also listed in the table, such as for Green Transformational Leadership (n = 5), Sustainable Performance (n = 4), and Corporate Social Responsibility (n = 3), as well as Management Commitment, Green Creativity and Green Intellectual Capital, with 2 occurrences each.Table 7 includes the top 20 keywords on the basis of the maximum number of cooccurrences.Green Innovation occurred the highest number of times (n = 18), forming a maximum number of links with other keywords.The average publication year for Green Innovation was 2021.Next came Green Human Resource Management, which occurred 16 times, with an average of 16 links being publicized in 2020.The occurrences of some other keywords are also listed in the table, such as for Green Transformational Leadership (n = 5), Sustainable Performance (n = 4), and Corporate Social Responsibility (n = 3), as well as Management Commitment, Green Creativity and Green Intellectual Capital, with 2 occurrences each.
Keyword co-occurrence analysis assists future scholars in understanding the current evolution of the themes along with research gaps for future investigations.As seen in the table, phrases such as Green Transformative Leadership, CSR, and Green Product Innovation appear after the primary keywords, indicating that scholars are delving into these topics alongside GHRM and Green Innovation.Furthermore, Green Innovation is largely studied in manufacturing industries.
Keywords that appeared the least reveal gaps for future research, such as investigating the impact of green creativity, green human capital, and management commitment along with GHRM on Green Innovation.Keyword co-occurrence analysis assists future scholars in understanding the current evolution of the themes along with research gaps for future investigations.As seen in the table, phrases such as Green Transformative Leadership, CSR, and Green Product Innovation appear after the primary keywords, indicating that scholars are delving into these topics alongside GHRM and Green Innovation.Furthermore, Green Innovation is largely studied in manufacturing industries.
Keywords that appeared the least reveal gaps for future research, such as investigating the impact of green creativity, green human capital, and management commitment along with GHRM on Green Innovation.

Discussion
GHRM and green innovation have been studied independently for the past few decades.Recently, scholars have increasingly focused on the imperative role of GHRM practices in driving green innovation.In the past decade, various studies found that GHRM practices play a vital role in green innovation.Some scholars have explored the direct impact [30,40], and some have studied it with the inclusion of mediating variables that lead toward other attractive outcomes, such as environmental performance [41].Moreover, some have also investigated various moderators (i.e., leadership styles) that strengthen the relationship of GHRM and green innovation [42,43].Table 8 presents the findings of the major studies.

Summary of Relationship between GHRM and Green Innovation
Saturnino Neto et al. [44] Green Training is positively related to Green Innovation in producing low Carbon Products, ultimately reducing the environmental emissions Bossle et al. [30] GHRM is considered as an internal factor with a positive influence on Green Innovation in an organization Jia et al. [29] GHRM along with Green Passion have a positive impact on Green Creativity El-Kassar and Singh [28] HR Practices considered as the drivers of Green Innovation lead to Competitive Advantage of the firm Yong et al. [45] Factors leading to GHRM will help the organization to be sustainable by Green Innovation

Sobaih et al. [46]
GHRM is indirectly positively related to Environmental Performance through Green Innovation as a mediator Malik et al. [19] GHRM helps in inducing Green Innovation through Green Creativity Green Innovation acts as a mediator between GHRM and Environmental Performance of the firm Shah and Soomro [40] Different practices of GHRM are in positive association with Green Innovation and behaviors that are voluntary and task oriented in nature 4.1.GHRM Practices and Green Innovation GHRM practices have been linked with green innovation; a few notable studies particularly focused on green training and appraisals.In 2014, a research study empirically investigated the relationship between green training and eco-innovation [44].Later, an-other study included performance appraisal along with green training in the presence of innovative culture in the organization; innovative culture was taken as a moderator to strengthen the relationship between the GHRM practices (green training and performance appraisal) and green innovation [42].Further, another study put forth its findings by considering a moderator through exploring the relationship between GHRM and environmental performance, with green innovation as a mediator and servant leadership as a moderator [43].However, there is a need to study other GHRM practices, i.e., green recruitment, compliance, reward and recognition and knowledge sharing.
A study concluded that green innovation, resulting from green creativity, is important for survival of the organizations [29].This study explored the variables GHRM, green passion and green creativity along with green transformational leadership and summarized that these are all important for green innovation.Studies investigated the mediating role of various variables such as green creativity [19], green organizational commitment [47], and green culture [41] between GHRM and green innovation.Further, a study also explored intervention of green human capital and environmental knowledge between GHRM and green innovation in the presence of managerial environmental concerns [20].

GHRM and Organizational Outcomes
Scholars investigated the relationship between GHRM and green innovation along with other outcome variables, i.e., environmental performance, financial performance and organizational identity.A study explored the impact of GHRM on green innovation and further included environmental performance in the model.This study aimed to check how GHRM led to green innovation, which altogether enhanced the environmental performance of small lodging enterprises in Egypt [46].Another scholar studied the same model in the chemical industry of Lahore, Pakistan [51], and a similar study conducted on manufacturing firms in Palestine also reported similar findings [53].Further, another study introduced the moderation of servant leadership to investigate the relationship between GHRM and environmental performance, with green innovation as a mediator in the context of the Indian IT sector [43].Later, in 2022, a scholar included big data along with GHRM to examine its impact on green innovation, which further led to enhanced environmental performance in the service industry of Oman [48].One of the studies particularly considered financial performance of the firm as a final outcome of GHRM, where the mediating role of green innovation was accessed between GHRM and financial performance [50].Moreover, a study on manufacturing firms in Malaysia included green culture along with green innovation as mediators between GHRM and environmental performance [41].

GHRM and Green Innovation Supporting Theories
Studies show that green innovation mediates between GHRM and environmental performance [41,43,53] mostly on the basis of the resource base view (RBV) theory.The impact of GHRM and green innovation (as a mediator) can be investigated on variables other than environmental performance.Studies proved the positive impact of GHRM on green organizational citizenship behavior on the basis of ability motivation opportunity (AMO) theory [54], green organizational identity on the theoretical basis of social identity theory [55], and corporate social responsibility (CSR) practices [56] and organizational commitment on the basis of AMO theory [57].Energy efficiency [58] and economic performance [59] are also outcomes of GHRM, which is also supported by AMO theory.

Future Recommendations
Based on the summary of the results discussed in Table 8, this study provides directions for future researchers to further investigate the impact of GHRM on green innovation, along with the inclusion of suggested variables.Figure 8 shows research gaps that future studies can take into consideration.White-shaded variables indicate that sufficient studies have been conducted in the context of GHRM and green innovation, whereas grey areas indicate that relatively few studies have been conducted.
formance [59] are also outcomes of GHRM, which is also supported by AMO theo

Future Recommendations
Based on the summary of the results discussed in Table 8, this study provides tions for future researchers to further investigate the impact of GHRM on green i tion, along with the inclusion of suggested variables.Figure 8 shows research ga future studies can take into consideration.White-shaded variables indicate that su studies have been conducted in the context of GHRM and green innovation, where areas indicate that relatively few studies have been conducted.In this bibliometric analysis, a majority of the articles considered GHRM as a pendent variable and green innovation as a dependent variable.Common GHRM tices of recruitment, training and development, appraisal and recognition were c ered in the sample articles.However, other GHRM practices, such as green know sharing, environmental compliance and corporate environmental disclosure, were amined in relation to green innovation.Moreover, future researchers should focus relative importance of GHRM practices such as green trainings, green compen green performance management, and green rewards and how these factors are ind ally impacting green innovation, so one can know which are the substantial GHRM tices in bringing green innovation.In bibliometric analysis, a majority of the articles considered GHRM as an independent variable and green innovation as a dependent variable.Common GHRM practices of recruitment, training and development, appraisal and recognition were considered in the sample articles.However, other GHRM practices, such as green knowledge sharing, environmental compliance and corporate environmental disclosure, were not examined in relation to green innovation.Moreover, future researchers should focus on the relative importance of GHRM practices such as green trainings, green compensation, green performance management, and green rewards and how these factors are individually impacting green innovation, so one can know which are the substantial GHRM practices in bringing green innovation.
A recent study explored the positive relation between GHRM and green innovation in the presence of green transformational leadership (moderator).The findings of the study were supported by AMO and RBV theories [60].Another study explored servant leadership as a moderator to prove the same relationship on the basis of AMO theory [43].Considering the theoretical grounds, some other leadership styles such as follower leadership, transactional leadership, and ebullient leadership can be studied as moderators between GHRM and green innovation.Moreover, top management support has been studied in relation to GHRM [61], and few studies also explored whether top management support plays a significant role in green innovation [62].However, the moderating role needs to be explored.
Past studies investigated the mediation of variables such as green creativity [19] and green human capital [20] between GHRM and green innovation.Apart from green innovation, GHRM practices are also linked with other environment-related variables, i.e., green training is associated with environmental performance [63], green passion mediates between GHRM and green creativity [29], and green self-efficacy and employee green behavior act as mediators between GHRM and environmental performance [64].Similarly, psychological green climate acts as an intervening variable between GHRM and employee green behavior [65].Currently, there is a need to study what additional employeerelated factors further lead to green innovation.Studies proposed that the above-mentioned internal factors such as green motivation, green passion, pro-environmental behavior, psychological green climate, and green self-efficacy should be studied to determine whether they serve as a mediators between GHRM and green innovation.Especially, the roles green self-efficacy and psychological green climate need to be further explored in the GHRM and green innovation context.Limited studies were found where organizational level variables were investigated as mediators, such as perceived organizational support, which was conceptualized as a mediator between GHRM and environmental performance [66].Future studies should explore and investigate the roles of organization level variables.
Scholars have investigated the relationship between GHRM and green innovation from various industrial perspectives, including the hotel industry [20], real estate sector [67], tourism industry [68], small-scale lodging sector [46], fertilizer industry [50], textile industry [69], food industry [39], large-scale manufacturing firms [21], etc. Future researchers can particularize the bibliographic analysis to specific industries, such as investigating the relationship between GHRM and green innovation in the hospitality industry, manufacturing industry, services industry, etc.
Middle Eastern countries and institutions are major contributors in this domain.A deeper exploration or hypothesis of why countries in the Middle East are leading could provide more contextual understanding.Future researchers can also dig into the secondary data research for this purpose.They can find measures mentioned in corporate annual sustainability reports that can be used to measure GHRM and green innovation.Primary research has been the main focus in this regard; however, secondary data research can be conducted to investigate the relationship between GHRM and green innovation.

Limitations
This study used the Scopus database for the extraction of the data.Although most of the reputed journals are indexed in both Scopus and Web of Science databases, there are a few Web of Science (WOS) Journals that are not indexed in the Scopus database.Therefore, future researchers can also consult the WOS database for bibliometric analysis in the respective domains.

Conclusions
GHRM practices have been identified as a major driver of green innovation; however, there was no comprehensive bibliometric study.In this regard, this study conducted a bibliometric analysis of articles published in the Scopus database.The study provides novel insights for researchers and practitioners to comprehend major developments in the domain, and also provides directions to build on future studies.
Summarizing the major findings of the study, yearly publications and citation trends showed upward growth, indicating the significance of this research domain."Environmental Science and Pollution Research", "Sustainability (Switzerland)" and "Technological Forecasting and Social Change" are leading journals, and interested scholars can focus on these journals for the latest developments in this particular domain.The Middle East, China and Pakistan are major contributors in this domain, so there are many opportunities for collaboration in these regions.Based on the bibliometric analysis, it can be concluded that GHRM plays a substantial role in green innovation and there is a strong need to conduct studies on contextual variables to further elaborate its impact on green innovation.

Figure 1 .
Figure 1.PRISMA Approach for Screening Data.Figure 1. PRISMA Approach for Screening Data.

Figure 1 .
Figure 1.PRISMA Approach for Screening Data.Figure 1. PRISMA Approach for Screening Data.

2 "
Green innovation and environmental performance: The role of green transformational leadership and green human resource management" "Green innovation and organizational performance: The influence of big data and the moderating role of management commitment and HR practices"

Figure 6 .
Figure 6.Documents highlighted by bibliographic coupling analysis.

Figure 6 .
Figure 6.Documents highlighted by bibliographic coupling analysis.

Table 1 .
Yearly Citation of Articles.

Table 1 .
Yearly Citation of Articles.
"Green innovation and environmental performance: The role of green transformational leadership and green human resource management"

Table 6 .
Co-Authorship by Different Countries.

Table 8 .
Summary on Linkages between GHRM and Green Innovation.