- Author: Roman Loimeier
- Language: English
- Year: 2016
- Author: Roman Loimeier
- Language: German
- Year: 2014
- Author: Professor Roman Loimeier
- Language: English
- Year: 2016
- Author: Roman Loimeier
- Language: German
- Year: 2021
- Author: John O. Hunwick, Rex Séan O'Fahey, Razaq Abubakre, Hamidu Bobboyi, Roman Loimeier, Stefan Reichmuth, Muhammad Sani Umar
- Language: English
- Year: 1995
- Author: Roman Loimeier
- Language: English
- Year: 2013