- Author: Rolf Porst (auth.)
- Language: German
- Year: 2014
- Author: Marco Giesselmann Michael Windzio (auth.)
- Language: German
- Year: 2012
- Author: Dr. phil. Hans-Dieter Schneider (auth.)
- Language: German
- Year: 1975
- Author: Dipl.-Soz. Wolfgang Felber (auth.)
- Language: German
- Year: 1986
- Author: Professor Dr. rer. pol. Thomas A. Herz (auth.)
- Language: German
- Year: 1983
- Author: Paul B. Hill Johannes Kopp (auth.)
- Language: German
- Year: 2013
- Author: Heiner Meulemann (auth.)
- Language: German
- Year: 2013
- Author: Prof. Dr. Heinz Sahner (auth.)
- Language: German
- Year: 2002
- Author: Paul B. Hill Johannes Kopp (auth.)
- Language: German
- Year: 2004
- Author: Paul B. Hill Johannes Kopp (auth.)
- Language: German
- Year: 2002