| article html file updated | 7 February 2020 19:54 CET | Update | https://www.mdpi.com/2077-0375/6/4/57 |
| article html file updated | 4 May 2019 18:37 CEST | Update | - |
| article html file updated | 28 December 2016 08:01 CET | Update | - |
| article html file updated | 19 December 2016 09:39 CET | Original file | - |
| article xml uploaded. | 19 December 2016 09:38 CET | Original file | https://www.mdpi.com/2077-0375/6/4/57/xml |
| article pdf uploaded. | 19 December 2016 09:38 CET | Version of Record | https://www.mdpi.com/2077-0375/6/4/57/pdf |
