- Author: Debbie M. Schell, Kurt A. Wagner, Richard E. Schell
- Language: Spanish
- Year: 2007
- Author: Wagner Richard
- Language: Spanish
- Author: Wagner Richard
- Language: Spanish
- Author: Wagner Richard
- Language: Spanish
- Author: Wagner Richard, Newman Ernest
- Language: English
- Year: 1933
- Author: Wagner Richard, Magee Bryan
- Language: English
- Year: 2001
- Author: Wagner Richard, Berger William
- Language: English
- Year: 1998
- Author: Wagner Richard, Berger William
- Language: English
- Year: 1998
- Author: Wagner Richard, Brener Milton E
- Language: English
- Year: 2006
- Author: Schacht Richard, Wagner Richard, Kitcher Philip
- Language: English
- Year: 2004