| article html file updated | 7 February 2020 21:46 CET | Update | https://www.mdpi.com/2220-9964/6/1/21 |
| article html file updated | 22 September 2019 23:03 CEST | Update | - |
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| article html file updated | 8 February 2017 09:02 CET | Update | - |
| article html file updated | 19 January 2017 10:04 CET | Original file | - |
| article xml uploaded. | 19 January 2017 10:03 CET | Original file | https://www.mdpi.com/2220-9964/6/1/21/xml |
| article pdf uploaded. | 19 January 2017 10:03 CET | Version of Record | https://www.mdpi.com/2220-9964/6/1/21/pdf |
