Tower drafting compass

Chicago citation style
Tower drafting compass. 193u~. Retrieved from the Digital Public Library of America, http://archives-dc.library.caltech.edu/islandora/object/ct1%3A6775. (Accessed December 12, 2018.)
APA citation style
(193u~) Tower drafting compass. Retrieved from the Digital Public Library of America, http://archives-dc.library.caltech.edu/islandora/object/ct1%3A6775
MLA citation style
Retrieved from the Digital Public Library of America <http://archives-dc.library.caltech.edu/islandora/object/ct1%3A6775>.
Note: These citations are programmatically generated and may be incomplete.