Lyman M. Kells, Willis F. Kern & James R. Bland.
K and E manual: Log log duplex decitrig slide rule number N4081.
R601147. K and E manual: Log log duplex decitrig slide rule number N4081. By Lyman M. Kells, Willis F. Kern & James R. Bland. NM: revisions. © 10Dec47; AA115114. Keuffel and Esser Company (PWH); 20Mar75; R601147.
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