I agree with Chaffee's list and would put a plug in for George Garton's, Colt's SAA: Post War Models (1979). Not as in depth as Wilkerson but a good solid overview of the various Post-War SAAs, New Frontiers, and Colt single action .22s. Garton also has good information on the various commemoratives. Plus you can buy it pretty reasonable (under $40 from Amazon) from several sources.