| article html file updated | 6 February 2020 09:27 CET | Update | https://www.mdpi.com/2227-9040/2/2/121 |
| article html file updated | 7 May 2019 14:10 CEST | Update | N/A |
| article html file updated | 21 March 2019 17:30 CET | Update | N/A |
| article html file updated | 20 August 2015 08:01 CEST | Original file | N/A |
| article pdf uploaded. | 23 May 2014 09:57 CEST | Version of Record | https://www.mdpi.com/2227-9040/2/2/121/pdf |
