Hien, Do Ngoc, Minh Ly Duc, and Tran Duc Tuan. “Integrating Six Sigma into an Industry 4.0 System for Enhanced Productivity: A Case Study in CNC Processes”. Management and Production Engineering Review 15, no. 1 (March 30, 2024): 44–62. Accessed September 20, 2026. https://wydawnictwo.pan.pl/index.php/mper/article/view/5548.