- Author: Kornelia van der Beek, Gregor van der Beek, Wilfried Boroch
- Language: German
- Year: 2023
- Author: Kornelia van der Beek, Gregor van der Beek, Wilfried Boroch
- Language: German
- Year: 2023
- Author: Thorsten Korn, Jakob Lempp, Gregor van der Beek
- Language: German
- Year: 2023
- Author: Kornelia van der Beek, Gregor van der Beek
- Language: German
- Year: 2012
- Author: Klaus Tiepelmann (editor), Gregor van der Beek (editor)
- Language: German
- Year: 1992
