- Author: Stevenson Mark
- Language: English
- Year: 2018
- Author: Tillmann Michael, Offe Claus, Vanderborght Yannick, Van Parijs Philippe
- Language: German
- Year: 2005
- Author: Sebesta Robert W
- Language: English
- Year: 2015
- Author: Bartlett Robert E
- Language: English
- Year: 1997