- Author: Douglas N. Walton, Erik C. W. Krabbe
- Language: Spanish
- Year: 2017
- Author: Douglas N. Walton
- Language: English
- Year: 2013
- Author: Douglas N. Walton
- Language: Portuguese
- Year: 2012
- Author: Douglas N. Walton
- Language: English
- Year: 1998
- Author: Douglas N. Walton Eric C. W. Krabbe
- Language: Spanish
- Year: 2017
- Author: Douglas N. Walton
- Language: English
- Year: 1999
- Author: Douglas N. Walton
- Language: English
- Year: 1995
- Author: Douglas N. Walton
- Language: English
- Year: 1997
- Author: Douglas N. Walton
- Language: English
- Year: 2002
- Author: Douglas N. Walton
- Language: English
- Year: 2003