Pongpalanchai N, Ratanakuakangwan S. Improving the purchasing process for spare parts in a Petrochemical Plant. IENJ [internet]. 2015 Jul. 13 [cited 2026 Sep. 10];1(2):16-22. available from: https://ph02.tci-thaijo.org/index.php/ienj/article/view/180362