| article html file updated | 6 February 2020 04:52 CET | Update | https://www.mdpi.com/2076-0787/2/4/439 |
| article html file updated | 20 September 2019 01:55 CEST | Update | N/A |
| article html file updated | 7 May 2019 23:23 CEST | Update | N/A |
| article html file updated | 21 March 2019 05:53 CET | Original file | N/A |
| article pdf uploaded. | 14 October 2013 16:15 CEST | Version of Record | https://www.mdpi.com/2076-0787/2/4/439/pdf |
