- Author: Dr. Helmut Bähring (auth.)
- Language: German
- Year: 2005
- Author: Dr. Helmut Bähring (auth.)
- Language: German
- Year: 2002
- Author: Dr. Helmut Bähring (auth.)
- Language: German
- Year: 1994
- Author: Dr. Helmut Bähring (auth.)
- Language: German
- Year: 1991
- Author: Dr. Helmut Bähring (auth.)
- Language: German
- Year: 2002