| article html file updated | 6 February 2020 03:59 CET | Update | https://www.mdpi.com/2221-3759/1/2/141 |
| article html file updated | 8 May 2019 01:16 CEST | Update | - |
| article html file updated | 21 March 2019 03:35 CET | Update | - |
| article html file updated | 17 June 2015 12:40 CEST | Original file | - |
| article pdf uploaded. | 26 August 2013 13:50 CEST | Version of Record | https://www.mdpi.com/2221-3759/1/2/141/pdf |
