- Author: Meyer-Sparenberg Wolfgang
- Language: German
- Year: 1990
- Author: Mellinghoff Georg
- Language: German
- Year: 1988
- Author: Maiberg Karin
- Language: German
- Year: 2003
- Author: Liedmeier Norbert
- Language: German
- Year: 1991
- Author: Lauber-Nöll Achim
- Language: German
- Year: 1993
- Author: Lackhoff Klaus
- Language: German
- Year: 2000