Hafudh Al-Deffa’e, Asa’d. 2009. “The Effect of Pre-Used Oil of Cars Mixed With Salt Resistance Cement on Collapsibility of Gypseous Soil”. Journal of Engineering and Sustainable Development 13 (1): 47-57. https://jeasd.uomustansiriyah.edu.iq/index.php/jeasd/article/view/1528.