Adil, E., K. Omer, S. Longcang, and H. zenchun. “Hydrogeologic and Hydrochemical Investigation of Aquifers in Semi-Rid Area, Central Sudan”. Malaysian Journal of Science, vol. 22, no. 2, Aug. 2003, pp. 105-12, https://juku.um.edu.my/index.php/MJS/article/view/8524.