- Author: Bernhard Gahm
- Language: English
- Year: 1998
- Author: Rudolf Metzner
- Language: German
- Year: 1991
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- Language: German
- Author: Helmut Pirc
- Language: German
- Year: 2008
- Author: Eva Schumann
- Language: German
- Year: 2011
- Author: Achim Samwald
- Language: German
- Year: 2007
- Author: Robert Cunning
- Language: German
- Year: 2000
- Author: Egon Binder
- Language: German
- Year: 2009
