Six Sigma (Quality control standard)

Design for Six Sigma for green belts and champions by: Gitlow, Howard S.; Levine, David M.; Popovich, Edward A. (Language materials, printed)

Demystifying Six Sigma : a company-wide approach to continuous improvement by: Larson, Alan (Language materials, printed)

Lean Six Sigma for service : How to use Lean Speed and Six Sigma Quality to improve services and transactions by: George, Michael L. (Language materials, printed)