For my dollar (which is 75 cents US) you can't beat the two books by Jack Sobon for all aspects of traditional timber framing. His second book covers square rule in a more formal way. Also Will Beemer had a series of articles for the beginner timber framer in Timber Framing (Journal of the Timber Framers Guild). One of his series dealt with the various layout methods. Finally I believe Jack Sobon has written (possibly in the journal)something specifically about the square rule method. I remember seeing a reference to this but don't recall the particulars. I am new to this game and am sure you will get alot of good recommendations from others.
Norm
