Neubecker, Ottfried. Heraldry: Symbols, Sources, and Meaning. McGraw-Hill, England:1976
Pine, L.G. The Story of Heraldry. Country Life Ltd., London:1953
Woodcock, Thomas and Robinson, John Martin. The Oxford Guide to Heraldry. Oxford niversity Press, Oxford:1988
Additional backround information obtained from Fox-Davies, 2 books I've forgotten but will add later when I find my notes, and Velde's heraldica.org.