United States. War Dept. Elementary map and aerial photograph reading. Washington, D.C.. UNT Digital Library. http://digital.library.unt.edu/ark:/67531/metadc96653/. Accessed July 13, 2014.
Note: Inconsistencies in capitalization and punctuation within the Digital Library may affect this citation. Before using this citation in formal writing, please consult your preferred style manual. More information.