Oladimeji O.A, Ikotun D.O., Ademuyiwa J.A., and Olaniyan J.O. 2020. “Analysis of Crude Oil Prodction in Nigeria by Servicing Companies”. Global Journal of Science Frontier Research 20 (F9):41-57. https://journalofscience.org/index.php/GJSFR/article/view/2859.