Ali Sami Hashem, Prof. Dr. Faiq Muhammad Sarhan Al-Zwainy. “Factors Affecting in Estimation of Durations and Costs for Oil Projects: A Systematic Literature Review”. Mathematical Statistician and Engineering Applications 71, no. 4 (September 23, 2022): 3354–3367. Accessed March 4, 2026. https://www.philstat.org/index.php/MSEA/article/view/896.