- Author: Harold G. Vatter, John F. Walker
- Language: English
- Year: 2019
- Author: Harold G. Vatter
- Language: English
- Year: 2019
- Author: John F. Walker Harold G. Vatter
- Language: English
- Year: 2015
- Author: Harold G. Vatter, John F. Walker
- Language: English
- Year: 2015