| article html file updated | 6 February 2020 04:16 CET | Update | https://www.mdpi.com/1996-1073/6/9/4721 |
| article html file updated | 8 May 2019 00:41 CEST | Update | N/A |
| article html file updated | 21 March 2019 04:19 CET | Update | N/A |
| article html file updated | 18 January 2017 06:41 CET | Original file | N/A |
| article pdf uploaded. | 9 September 2013 15:46 CEST | Version of Record | https://www.mdpi.com/1996-1073/6/9/4721/pdf |
