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- Language: English
- Year: 2014
- Author: Robert W. Christopherson&Ginger H. Birkeland
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- Year: 2014
- Author: Robert W. Christopherson, Ginger Birkeland
- Language: English
- Year: 2017
- Author: Robert W. Christopherson Ginger H. Birkeland Philip Thomas Giles Mary-Louise Byrne
- Language: English
- Year: 2015
- Author: Robert W Christopherson
- Language: English
- Year: 2013
- Author: Robert W. Christopherson
- Language: English
- Year: 2011
- Author: Robert W. Christopherson
- Language: English
- Year: 2004
