DONAHUE, Wesley E. Unlocking Lean Six Sigma: A Competency-Based Approach to Applying Continuous Process Improvement Principles and Best Practices (Competency Based Books for Structured Learning). Pennsylvania: Centrestar Learning, 2021. 207 p.
ISBN 9798594575363 .
MALEYEFF, John. Quality Service Management: A Guide to Improving Business Processes. New York, Routledge, 2022. 198 p.
ISBN 9781032057514 .
MUNRO,R.,A.RAMU and D.ZRYMIAK. The Certified Six Sigma Black Belt. Handbook. 2nd edition. Milwaukee: ASQ, Quality Press, 2015. 620 p.
ISBN 978-0-87389-891-1.