- Author: Kate Narveson
- Language: English
- Year: 2016
- Author: James C. Wilhoit, Evan B. Howard, Jim Wilhoit
- Language: English
- Year: 2012
- Author: Fee Gordon D., Stuart Douglas K
- Language: English
- Year: 2009
- Author: Fee Gordon D., Stuart Douglas K
- Language: English
- Year: 2009
- Author: Carson D. A
- Language: English
- Year: 2006
- Author: Piper John
- Language: English
- Year: 2017
- Author: Kreeft Peter
- Language: English
- Year: 2005
- Author: Green Chris E. W.
- Language: English
- Year: 2015