- Author: Niklas Luhmann (editor), Javier Torres Nafarrate (editor)
- Language: Spanish, Castilian
- Year: 2006
- Author: Niklas Luhmann Javier Torres Nafarrate
- Language: Spanish
- Year: 2004
- Author: Brunhilde Erker, Niklas Luhmann, Silvia Pappe, Javier Torres Nafarrate
- Language: Spanish
- Year: 1998