- Author: Franz Riegel (auth.)
- Language: German
- Year: 1963
- Author: Franz Riegel (auth.)
- Language: German
- Year: 1958
- Author: Franz Riegel (auth.)
- Language: German
- Year: 1963
- Author: Franz Riegel (auth.)
- Language: German
- Year: 1964
- Author: Franz Riegel (auth.)
- Language: German
- Year: 1951