Shamaki, Muazu Alhaji, and Katiman Rostam. “Factors Affecting Maternal Mortality In Sokoto State, Nigeria: Faktor-Faktor Yang Mempengaruhi Kematian Semasa Hamil Di Negeri Sokoto, Nigeria”.
GEOGRAFI, vol. 1, no. 2, Oct. 2013, pp. 59-70,
https://ejournal.upsi.edu.my/index.php/GEOG/article/view/455.