Rank: The Story Behind Names of Different Rank
Why is the Colonel Called "Kernal"?
The Origin of the Ranks and Rank Insignia Now Used by the United States Armed Forces
by Raymond Oliver, Museum Curator for McClellan Aviation Museum
Published by the Office of History, Sacramento Air Logistics Center, McClellan AFB CA 95652, August 1983 [This hard to find publication is an excellent introduction to origins of naval and military ranks.]