- Author: Sales Profi · BDVT (auth.)
- Language: German
- Year: 2000
- Author: Dr. Horst G. Max (auth.)
- Language: German
- Year: 1996
- Author: Professor Dr. Karl-Heinz Rau (auth.)
- Language: German
- Year: 1991
- Author: Margit Warneke (auth.)
- Language: German
- Year: 1999
- Author: Dietrich Buchner (auth.) Dietrich Buchner (eds.)
- Language: German
- Year: 1998
- Author: Jürgen Dunsch (auth.) Andreas R. Voegele Sylvia Schindele (eds.)
- Language: German
- Year: 1998
- Author: Klaus A. Zimmermann (auth.)
- Language: German
- Year: 1996
- Author: Felix Hufeld Michael Wassiluk (auth.) Stefan A. Duvvuri Thomas Schäfer (eds.)
- Language: German
- Year: 1998
- Author: Anton Schmoll (auth.)
- Language: German
- Year: 1996