Yousif, L.
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 Mathematical models to predict repair and maintenance cost for 2WD tractors in the mechanized rainfed areas, eastern Sudan.
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Retrieved from <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>