Yearout, Robert D, and Claudel B McKenzie. “EDITORIAL: ‘Six Sigma - Its Application, Practice, and Utility’”. International Journal of Industrial Engineering: Theory, Applications and Practice 16, no. 3 (August 14, 2009): 160–161. Accessed June 19, 2026. https://www.ijietap.com/index.php/ijie/article/view/261.