JAUN, Marlon A. Lean Six Sigma Techniques. Books on Demand, 2021. 194 p. ISBN 3754308122 .
MALEYEFF, John. Quality Service Management: A Guide to Improving Business Processes. New York, Routledge, 2022. 198 p. ISBN 9781032057514 .
OAKLAND, John S. and Robert J. OAKLAND. Total Quality Management and Operational Excellence. 5th ed. New York: Routledge, 2021. 517 p. ISBN 978-1-138-67340-0 .