- Reza M. Pirasteh, PH.D., and Kimberly S. Farah, PH.D. - The Top Elements of TOC, Lean, and Six Sigma (TLS) Make Beautiful Music Together, APICS Magazine article, May 2006.
- Lean Enterprise Institute, 2004 and 2005 Surveys on Lean Manufacturing.
- Premo, Jason P., Please Help! My Lean Is Broken, Institute of Industrial Engineers.
- Survey by Celerant Consulting, December 2004.
- Reprinted with permission from The Ultimate Improvement Cycle – Maximizing Profits Through the Integration of Lean, Six Sigma, and the Theory of Constraints – CRC Press, Taylor & Francis Group, Boca Raton, FL, 2009
- Goldratt, Eliyahu M., The Goal (Great Barrington, MA: North River Press, 1986)
- Harry, Mikel, and Richard Schroeder, Six Sigma: The Breakthrough Management Strategy Revolutionizing the World’s Top Corporations (New York: Doubleday,2000).
- Pande, Peter S., Robert P. Newman, and Roland R. Cavanaugh, The Six Sigma Way—How GE, Motorola, and Other Top Companies Are Honing Their Performance (New York: McGraw-Hill, 2000).
- Womack, James P., and Daniel T. Jones, Lean Thinking—Banish Waste and Create Wealth in Your Corporation (New York: Free Press, 2003).