Almaliki, Salim A., Majed S. Himoud, and Sadiq J. Muhsin. “Mathematical Model for Evaluating Slippage of Tractor Under Various Field Conditions”. Basrah J. Agric. Sci. 34, no. 1 (February 9, 2021): 49–59. Accessed May 14, 2021. https://bjas.bajas.edu.iq/index.php/bjas/article/view/322.