Hussain Jawad, Ethar. “Statistical Methods for Controlling the Quality of Crude Oil Products in Iraq”. Journal of Economics and Administrative Sciences 29, no. 136 (June 5, 2023): 101–120. Accessed June 25, 2025. https://www.jeasiq.uobaghdad.edu.iq/index.php/JEASIQ/article/view/2611.