- Author: Clifford L. Penner, Joyce J. Penner
- Language: English
- Year: 2007
- Author: Clifford L. Penner
- Language: English
- Year: 2005
- Author: Clifford L. Penner, Joyce J. Penner
- Language: English
- Year: 2017
- Author: Clifford L. Penner, Joyce J. Penner
- Language: English
- Year: 2016
- Author: Clifford L. Penner, Joyce J. Penner
- Language: English
- Year: 2017
- Author: Joyce J. Penner, Clifford L. Penner
- Language: English
- Year: 2017