- Author: Europäische Union, European Union, De Vries Catherine E
- Language: English
- Year: 2018
- Author: Europäische Union, European Union, Tsoukalis Loukas
- Language: English
- Year: 2016
- Author: AEuropean Union, European Union, Kaiser Wolfram, Leucht Brigitte
- Language: English
- Year: 2009