| article html file updated | 6 February 2020 01:17 CET | Update | https://www.mdpi.com/1996-1073/6/4/1821 |
| article html file updated | 8 May 2019 06:46 CEST | Update | N/A |
| article html file updated | 20 March 2019 20:26 CET | Update | N/A |
| article html file updated | 17 February 2017 06:01 CET | Original file | N/A |
| article pdf uploaded. | 28 March 2013 15:44 CET | Version of Record | https://www.mdpi.com/1996-1073/6/4/1821/pdf |
