Dunbar

Chicago citation style
Geological Survey (U.S. Dunbar. 1972. Retrieved from the Digital Public Library of America, http://content.wisconsinhistory.org/cdm/ref/collection/maps/id/2250. (Accessed December 15, 2019.)
APA citation style
Geological Survey (U.S, (1972) Dunbar. Retrieved from the Digital Public Library of America, http://content.wisconsinhistory.org/cdm/ref/collection/maps/id/2250
MLA citation style
Geological Survey (U.S. Retrieved from the Digital Public Library of America <http://content.wisconsinhistory.org/cdm/ref/collection/maps/id/2250>.
Note: These citations are programmatically generated and may be incomplete.