| article html file updated | 6 February 2020 04:15 CET | Update | https://www.mdpi.com/1996-1073/6/9/4639 |
| article html file updated | 8 May 2019 00:44 CEST | Update | N/A |
| article html file updated | 21 March 2019 04:15 CET | Update | N/A |
| article html file updated | 13 February 2017 08:47 CET | Original file | N/A |
| article pdf uploaded. | 9 September 2013 10:27 CEST | Version of Record | https://www.mdpi.com/1996-1073/6/9/4639/pdf |
