YOUSIF, Lotfie A..
 Mathematical models to predict repair and maintenance cost for 2WD tractors in the mechanized rainfed areas, eastern Sudan.
<strong>Gezira Journal of Agricultural Science</strong>, [S.l.], v. 14, n. 1, jan. 2016.
ISSN 1728-9556. Available at: &lt;<a href="http://journals.uofg.edu.sd/index.php/gjas/article/view/133" target="_new">http://journals.uofg.edu.sd/index.php/gjas/article/view/133</a>&gt;. Date accessed: 21 july 2026.