Sources for information about Precision versions include:
- Precision Today, 2nd Edition, by David Berkowitz and Brent Manley, DBM Publications, Memphis, TN, 2010.
- Enhanced Precision, 2nd Edition, by Ronald Beall. Order from http://www.bridgeworld.com.
- The online notes of Oliver Clarke at http://pigpen.org.uk/BBO/index.php.
- Power Precision, by Alan Sontag, William Morrow & Co, N.Y., N.Y. (1979)
- Standard Modern Precision: Getting From Here To There, by Daniel O’Neill (2011). Avalable e-book online at bridgewithdan.com.
I’d also like to thank partners Yih-Renn Kan, John Engstrom, and the late Dennis Tretheway for their insights and suggestions.