- Author: Friedrich Engels
- Language: Turkish
- Year: 2018
- Author: Jeremy David Engels
- Language: English
- Year: 2018
- Author: Michael Rath-Glawatz, Stefan Engels, Torsten Giebel, Christian Dietrich
- Language: German
- Year: 2005
- Author: Engels Nicole
- Language: German
- Year: 2001
- Author: Engels Andreas
- Language: German
- Year: 2008
- Author: Jens Ivo Engels, Frédéric Monier
- Language: English
- Year: 2020
- Author: Jens Ivo Engels, Andreas Fahrmeir, Frédéric Monier, Olivier Dard
- Language: German
- Year: 2015
- Author: David Engels
- Language: German
- Year: 2021
