Umaru, M. ., M. . Dalhatu, A. . Bello, and H. . Nawawi. “Animal Traction As Source of Farm Power in Rural Areas of Sokoto State, Nigeria”. Health, Safety and Environment , vol. 1, no. 1, May 2013, pp. 23-28, https://sjournals.com/index.php/hse/article/view/406.