- Author: Jochum Georg
- Language: German
- Year: 1997
- Author: Hohberger Stefan
- Language: German
- Year: 2008
- Author: Hildebrand Daniel
- Language: German
- Year: 2011
- Author: Henkel Michael
- Language: German
- Year: 1999
- Author: Henkel Michael, Lembcke Oliver W.
- Language: German
- Year: 2010
- Author: Helmert Gundula
- Language: German
- Year: 1996