Sources for information about Precision versions include:

  1. Standard Modern Precision: Getting From Here To There, by Daniel O’Neill (2011). Avalable e-book online at
  2. Precision Today, 2nd Edition, by David Berkowitz and Brent Manley, DBM Publications, Memphis, TN, 2010. (out of print)
  3. Enhanced Precision, 2nd Edition, by Ronald Beall. Order from
  4. The online notes of Oliver Clarke at
  5. Power Precision, by Alan Sontag, William Morrow & Co, N.Y., N.Y. (1979)
  6. Notes of Robert Walters, San Diego, private communication.

I’d also like to thank partners John Engstrom, Robert Walters, Yih-Renn Kan, and the late Dennis Tretheway for their insights and suggestions.