- Author: Jochen Schröder
- Language: German
- Year: 1990
- Author: Joachim Buscha
- Language: German
- Year: 1989
- Author: Theodor Berberoff Peter Rankoff
- Language: German, Bulgarian
- Year: 1971
- Author: K. A. Paffen
- Language: German
- Year: 1970
- Author: Hans-Jürgen Grimm
- Language: German
- Year: 1987
- Author: Theodor Berberoff Dr. Peter Rankoff
- Language: German, Bulgarian
- Year: 1971
- Author: Heinz Fähnrich
- Language: German
- Year: 1986
- Author: Siegmund Brauner
- Language: German
- Year: 1974