- Author: Michael Kemper, Raoul Motika, Stefan Reichmuth
- Language: English
- Year: 2009
- Author: John O. Hunwick, Rex Séan O'Fahey, Razaq Abubakre, Hamidu Bobboyi, Roman Loimeier, Stefan Reichmuth, Muhammad Sani Umar
- Language: English
- Year: 1995
- Author: Stefan Reichmuth
- Language: English
- Year: 2012