This is my last entry on this topic. I've had my say. Perhaps the dialog has been useful to someone. I suggest that you add your references  I think the older ones are wonderful i.e. Huffman, Mealy, Moore. I looked for Shannon's stuff but have been unsuccessful so far in finding anything except references  back to the 1930's. I am still curious. I suggest you consider the quotations (Minsky, Kozen, Cannon) that I presented above. I may work on the state article to bring some of the various definitions out into the open. The next time I get to the library I will explore your references. You may see a bit of movement of bibliographic/references stuff around as I explore more. wvbailey