| article html file updated | 7 February 2020 01:14 CET | Update | https://www.mdpi.com/2227-9709/2/4/50 |
| article html file updated | 9 January 2020 14:45 CET | Update | - |
| article html file updated | 27 October 2017 10:29 CEST | Original file | - |
| article pdf uploaded. | 20 November 2015 12:20 CET | Version of Record | https://www.mdpi.com/2227-9709/2/4/50/pdf |
| article xml uploaded. | 20 November 2015 12:20 CET | Original file | https://www.mdpi.com/2227-9709/2/4/50/xml |
