De FEO, J. A., & BARNARD, W. W. (2005). Juran institute's six sigma breakthrough and beyond: Quality performance breakthrough methods. Tata McGraw-Hill.

De FEO, Joseph A., and William W. BARNARD. Juran Institute's Six Sigma Breakthrough and Beyond: Quality Performance Breakthrough Methods. New Delhi: Tata McGraw-Hill, 2005.

De FEO, Joseph A., and William W. BARNARD. Juran Institute's Six Sigma Breakthrough and Beyond: Quality Performance Breakthrough Methods. Tata McGraw-Hill, 2005.