Osama Hawi Aziz Al-Tai / Mahmood Fahad Abid Ali Al-Dulami 2022. The strategy S5 and its role in reducing product cost An analytical study of the opinions of a sample of workers in the production department of the Central Refineries Company. (Humanities, social and applied sciences) Misan Journal of Academic Studies . 21, 44 (Dec. 2022), 149-171.