| article html file updated | 7 February 2020 03:23 CET | Update | https://www.mdpi.com/2079-9721/4/1/2 |
| article html file updated | 6 May 2019 02:41 CEST | Update | - |
| article html file updated | 26 March 2019 18:20 CET | Original file | - |
| article xml uploaded. | 13 January 2016 11:17 CET | Original file | https://www.mdpi.com/2079-9721/4/1/2/xml |
| article pdf uploaded. | 13 January 2016 11:17 CET | Version of Record | https://www.mdpi.com/2079-9721/4/1/2/pdf |
