Ismail A, Bahri Mohamed S, Juahir H, Ekhwan Toriman M, Md. Kassim A, Md Zain S, et al. DMAIC Six Sigma Methodology in Petroleum Hydrocarbon Oil Classification. IJET [Internet]. 2018 Jul. 25 [cited 2024 Nov. 22];7(3.14):98-106. Available from: https://sciencepubco.com/index.php/ijet/article/view/16868