Breyfogle III, F. W. (2001).  Managing Six sigma: A practical guide to understanding, assessing, and implementing the strategy that yields bottom line success.  John Wiley & Sons.

 Breyfogle III, Forrest W.  Managing Six Sigma: A Practical Guide to Understanding, Assessing, and Implementing the Strategy That Yields Bottom Line Success.  John Wiley & Sons, 2001.

 Breyfogle III, Forrest W.  Managing Six Sigma: A Practical Guide to Understanding, Assessing, and Implementing the Strategy That Yields Bottom Line Success.  John Wiley & Sons, 2001.