- Author: Monika Andrae, Chris Marquardt
- Language: German
- Year: 2022
- Author: Monika Andrae
- Language: German
- Year: 2017
- Author: Chris Marquardt Monika Andrae
- Language: English
- Year: 2016
- Author: Chris Marquardt Monika Andrae
- Language: English
- Year: 2016
- Author: Chris Marquardt Monika Andrae
- Language: English
- Year: 2016