- Author: Margaret C. Wang, Herbert J. Walberg
- Language: English
- Year: 2007
- Author: Cbt., Madow Michelle, Riekert Eva
- Language: German
- Year: 2016
- Author: cbt, Madow Michelle, Riekert Eva
- Language: German
- Year: 2017
- Author: Margaret C. Wang & Herbert J. Walberg
- Language: English
- Year: 2007