| article html file updated | 7 February 2020 20:05 CET | Update | https://www.mdpi.com/1999-4907/8/1/4 |
| article html file updated | 4 May 2019 18:16 CEST | Update | - |
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| article html file updated | 30 December 2016 07:34 CET | Update | - |
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| article pdf uploaded. | 30 December 2016 07:33 CET | Updated version of record | https://www.mdpi.com/1999-4907/8/1/4/pdf |
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| article xml uploaded. | 22 December 2016 05:27 CET | Original file | - |
| article pdf uploaded. | 22 December 2016 05:27 CET | Version of Record | https://www.mdpi.com/1999-4907/8/1/4/pdf-vor |