| article html file updated | 6 February 2020 05:36 CET | Update | https://www.mdpi.com/2304-8158/2/4/507 |
| article html file updated | 7 May 2019 22:00 CEST | Update | - |
| article html file updated | 21 March 2019 07:48 CET | Update | - |
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| article html file updated | 19 August 2015 09:59 CEST | Original file | - |
| article pdf uploaded. | 18 November 2013 15:10 CET | Version of Record | https://www.mdpi.com/2304-8158/2/4/507/pdf |
