- Author: Gerd Balzer Christian Schorn (auth.)
- Language: English
- Year: 2015
- Author: Gerd Balzer Christian Schorn (auth.)
- Language: English
- Year: 2015
- Author: Gerd Balzer Christian Schorn (auth.)
- Language: German
- Year: 2014
- Author: Gerd Balzer Christian Schorn (auth.)
- Language: German
- Year: 2011