A photograph of a sign that declares oil discharge to be prohibited.

Chicago citation style
A photograph of a sign that declares oil discharge to be prohibited.. 1974-05-19. Retrieved from the Digital Public Library of America, http://digital.library.temple.edu/cdm/ref/collection/p15037coll3/id/53643. (Accessed December 14, 2018.)
APA citation style
(1974-05-19) A photograph of a sign that declares oil discharge to be prohibited.. Retrieved from the Digital Public Library of America, http://digital.library.temple.edu/cdm/ref/collection/p15037coll3/id/53643
MLA citation style
Retrieved from the Digital Public Library of America <http://digital.library.temple.edu/cdm/ref/collection/p15037coll3/id/53643>.
Note: These citations are programmatically generated and may be incomplete.