| article html file updated | 8 February 2020 03:23 CET | Update | https://www.mdpi.com/2504-186X/2/2/4 | 
| article html file updated | 24 September 2019 06:36 CEST | Update | - | 
| article html file updated | 4 May 2019 02:37 CEST | Update | - | 
| article html file updated | 19 April 2017 11:03 CEST | Update | - | 
| article xml uploaded. | 19 April 2017 11:02 CEST | Update | https://www.mdpi.com/2504-186X/2/2/4/xml | 
| article html file updated | 13 April 2017 08:42 CEST | Original file | - | 
| article pdf uploaded. | 13 April 2017 08:41 CEST | Updated version of record | https://www.mdpi.com/2504-186X/2/2/4/pdf | 
| article pdf uploaded. | 11 April 2017 14:46 CEST | Version of Record | https://www.mdpi.com/2504-186X/2/2/4/pdf-vor |