- Author: Clemens Richarz, Christina Schulz, Friedemann Zeitler
- Language: English
- Year: 2012
- Author: Clemens Richarz, Christina Schulz
- Language: English
- Year: 2013
- Author: Clemens Richarz, Christina Schulz
- Language: German
- Year: 2012
- Author: Clemens Richarz, Christina Schulz, Friedemann Zeitler
- Language: English
- Year: 2007
- Author: Clemens Richarz Christina Schulz
- Language: English
- Year: 2013