- Author: Snarrenberg Robert
- Language: English
- Year: 1997
- Author: Thomas Christensen
- Language: English
- Year: 2004
- Author: Johann Friedrich Daube
- Language: English
- Year: 2006
- Author: Johann Friedrich Daube
- Language: English
- Year: 2006
- Author: Ernst Kurth
- Language: English
- Year: 1991
- Author: Ernst Kurth
- Language: English
- Year: 1991
- Author: Leslie David Blasius
- Language: English
- Year: 1996