- Author: Gärditz Klaus Ferdinand, Keller Karen, Niesler André
- Language: German
- Year: 2020
- Author: Keller Karen
- Language: English
- Year: 2015
- Author: Keller Karen
- Language: English
- Year: 2015
- Author: Keller Karen.
- Language: Portuguese-English
- Author: Keller Karen.
- Language: Portuguese-English