Myrick, J., Burkhardt, T., Nelms, L., Patch, S. and Yearout, R. 2009. Professional Perceptions of Six Sigma’s Value. International Journal of Industrial Engineering: Theory, Applications and Practice. 16, 3 (Aug. 2009), 234–247. DOI:https://doi.org/10.23055/ijietap.2009.16.3.269.