www.mimf.com is a good place to start. Also Frank Ford's website at www.frets.com/ And look at George Gruhn's site.He was involved in a couple of coffee table books on American Guitars that have old Martins and Ditsons and all that. There are some accurate techincal drawings / plans of many instruments including mid 1800s stuff available through the Guild of American Luthiers. www.luth.org