- Author: Merrill F. Unger
- Language: English
- Year: 1974
- Author: Merrill F. Unger
- Language: English
- Year: 1991
- Author: Merrill F. Unger
- Language: English
- Year: 2005
- Author: Merrill F. Unger
- Language: English
- Year: 2006
- Author: Merrill F. Unger
- Language: English
- Year: 2006