United States base map

Chicago citation style
Geological Survey (U.S.). United States base map. 1911. Retrieved from the Digital Public Library of America, http://ark.digitalcommonwealth.org/ark:/50959/7h149z26d. (Accessed June 19, 2018.)
APA citation style
Geological Survey (U.S.), (1911) United States base map. Retrieved from the Digital Public Library of America, http://ark.digitalcommonwealth.org/ark:/50959/7h149z26d
MLA citation style
Geological Survey (U.S.). Retrieved from the Digital Public Library of America <http://ark.digitalcommonwealth.org/ark:/50959/7h149z26d>.
Note: These citations are programmatically generated and may be incomplete.