- Author: Joachim Schaper, Reinhard Gregor Kratz
- Language: English
- Year: 2020
- Author: Reinhard Gregor Kratz, Hermann Spieckermann
- Language: German
- Year: 2000
- Author: Reinhard Gregor Kratz
- Language: German
- Year: 2015
- Author: Reinhard Gregor Kratz
- Language: German
- Author: Reinhard Gregor Kratz
- Language: German
- Year: 1991
- Author: Reinhard Gregor Kratz
- Language: German
- Year: 2013
- Author: Reinhard Gregor Kratz
- Language: German
- Year: 2017