KELLS, LYMAN M.
The log log duplex decitrig slide rule, no.4081 (a manual) by Lyman M. Kells, Willis F. Kern & James R. Bland.
KELLS, LYMAN M. The log log duplex decitrig slide rule, no.4081 (a manual) by Lyman M. Kells, Willis F. Kern & James R. Bland. © 5Oct45; AA498892. Keuffel & Esser Co. (PWH); 13Dec72; R541617.
Keuffel & Esser Co.|PWH