- Author: Hermann Cremer, Robert B. Price, Helmut Burkhardt, Matthias Gockel
- Language: English
- Year: 2016
- Author: Helmut Burkhardt Fritz Grünzweig Fritz Laubach Gerhard Maier (edd.)
- Language: Italian
- Year: 2005
- Author: Helmut Burkhardt
- Language: German
- Year: 1988
- Author: Helmut Burkhardt Fritz Grünzweig Fritz Laubach Gerhard Maier
- Language: German
- Year: 2009
- Author: Helmut Burkhardt Fritz Grünzweig Fritz Laubach Gerhard Maier
- Language: German
- Year: 2009