"Looking upstream into Black Canyon toward Hoover damsite showing four diversion tunnel outlets."

Chicago citation style
Department of the Interior. Bureau of Reclamation. Engineering and Research Center. 5/18/1981-3/4/1988. "Looking upstream into Black Canyon toward Hoover damsite showing four diversion tunnel outlets.". 1933-02-25. Retrieved from the Digital Public Library of America, http://catalog.archives.gov/id/293813. (Accessed September 19, 2018.)
APA citation style
Department of the Interior. Bureau of Reclamation. Engineering and Research Center. 5/18/1981-3/4/1988, (1933-02-25) "Looking upstream into Black Canyon toward Hoover damsite showing four diversion tunnel outlets.". Retrieved from the Digital Public Library of America, http://catalog.archives.gov/id/293813
MLA citation style
Department of the Interior. Bureau of Reclamation. Engineering and Research Center. 5/18/1981-3/4/1988. Retrieved from the Digital Public Library of America <http://catalog.archives.gov/id/293813>.
Note: These citations are programmatically generated and may be incomplete.