Παραπομπή σε μορφή APA (7η εκδ.)

Simpson, A. (1954). The Nigerian coalfield: The geology of parts of Onitsha, Owerri, and Benue Provinces. By authority of the Nigerian Govt..

Παραπομπή σε μορφή Chicago (17η εκδ.)

Simpson, A. The Nigerian Coalfield: The Geology of Parts of Onitsha, Owerri, and Benue Provinces. [Zaria]: By authority of the Nigerian Govt., 1954.

Παραπομπή σε μορφή MLA (8th εκδ.)

Simpson, A. The Nigerian Coalfield: The Geology of Parts of Onitsha, Owerri, and Benue Provinces. By authority of the Nigerian Govt., 1954.