| article html file updated | 6 February 2020 06:21 CET | Update | https://www.mdpi.com/2071-1050/6/1/50 |
| article html file updated | 7 May 2019 20:34 CEST | Update | N/A |
| article html file updated | 21 March 2019 09:53 CET | Update | N/A |
| article html file updated | 19 August 2015 14:38 CEST | Original file | N/A |
| article pdf uploaded. | 20 December 2013 13:43 CET | Version of Record | https://www.mdpi.com/2071-1050/6/1/50/pdf |
