Seham Ismail, Alhatem Satta, Azizan As’arry, Salit Mohd Sapuan, and Jamal Tarique. “Improvement of Plastic Manufacturing Processes by Six Sigma and DMAIC Methods”. Applied Science and Engineering Progress 16, no. 3 (August 23, 2023): 6383. accessed January 8, 2026. https://ph02.tci-thaijo.org/index.php/ijast/article/view/250644.