Usman, A.M., M.A. Haque, and B. Umar. “Design, Construction and Evaluation of an Animal Drawn Disc Harrow”. ARID ZONE JOURNAL OF ENGINEERING, TECHNOLOGY AND ENVIRONMENT 4 (October 1, 2004): 37-44. Accessed September 14, 2025. http://www.azojete.com/index.php/azojete/article/view/320.