- Author: Norbert Varnholt, Peter Hoberg, Stefan Wilms, Uwe Lebefromm
- Language: German
- Year: 2023
- Author: Norbert Varnholt, Peter Hoberg, Stefan Wilms, Uwe Lebefromm
- Language: German
- Year: 2023
- Author: Norbert Varnholt, Peter Hoberg, Ralf Gerhards, Stefan Wilms
- Language: German
- Year: 2018
- Author: Norbert Varnholt, Uwe Lebefromm, Peter Hoberg
- Language: German
- Year: 2012