- Author: Robert J. Torrez, Robert Trapp
- Language: English
- Year: 2010
- Author: Karen A. Foss, Sonja K. Foss, Robert Trapp
- Language: English
- Year: 2002
- Author: Editors of IDEA Robert Trapp
- Language: English
- Year: 2009
- Author: Beth Dawson Robert Trapp
- Language: English
- Year: 2004