The polyphase duplex trig ... slide rule no. 4070
Subtitle: a manual
By: by Lyman M. Kells ... Willis F. Kern ... and James R. Bland ...
Contributors: Kern, Willis F. 1903-, joint author.; Bland, James R., joint author.
Publisher: Keuffel & Esser Co.
Published: 1939
Place of publication: New York; Hoboken, N.J. [etc.]
Language: eng
Number of pages: 87
Subjects: Slide-rule.
Notes: "Answers": p. 80-85.