Syarifudin, Achmad, Sri Ndaru Arthawati, and Sri Mukti Wirawati. “Quality Control of PCC (Portland Composite Cement) Using the Six Sigma Method at PT. XY”. Journal of Industrial Engineering & Management Research 7, no. 3 (May 30, 2026): 28-37. Accessed May 31, 2026. https://jiemar.org/index.php/jiemar/article/view/709.