| article html file updated | 6 February 2020 07:23 CET | Update | https://www.mdpi.com/2227-9040/2/1/69 |
| article html file updated | 7 May 2019 18:23 CEST | Update | - |
| article html file updated | 21 March 2019 12:39 CET | Update | - |
| article html file updated | 19 August 2015 21:13 CEST | Original file | - |
| article pdf uploaded. | 20 February 2014 15:54 CET | Version of Record | https://www.mdpi.com/2227-9040/2/1/69/pdf |
