KELLS, LYMAN M.
The log log duplex trig slide rule no.4080; a manual, by Lyman M. Kells, Willis F. Kern & James R. Bland.
KELLS, LYMAN M. The log log duplex trig slide rule no.4080; a manual, by Lyman M. Kells, Willis F. Kern & James R. Bland. © 29Dec43; AA462679. Keuffel & Esser Co. (PWH); 26Jul71; R509888.
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