
- Author: Carl Ritter
- Language: German
- Year: 1910

- Author: K. Ritter v. Endres
- Language: German
- Year: 1903

- Author: Gerhard A. Ritter
- Language: German
- Year: 2015

- Author: Carl Ritter (editor), Carl Ritter (editor), Justus Ritter (editor)
- Language: German
- Year: 1940

- Author: Harry van der Hulst (editor), Nancy Ritter (editor)
- Language: English
- Year: 1999

- Author: Paul Molitor, Jörg Ritter
- Language: German
- Year: 2012

- Author: Gerhard Ritter
- Language: German
- Year: 1948

- Author: Ulrich Peter Ritter
- Language: German
- Year: 1997