Do not disturb sign

Chicago citation style
Do not disturb sign. circa 1942-1945. Retrieved from the Digital Public Library of America, http://libx.bsu.edu/cdm/ref/collection/WWIIScrp/id/1191. (Accessed April 25, 2018.)
APA citation style
(circa 1942-1945) Do not disturb sign. Retrieved from the Digital Public Library of America, http://libx.bsu.edu/cdm/ref/collection/WWIIScrp/id/1191
MLA citation style
Retrieved from the Digital Public Library of America <http://libx.bsu.edu/cdm/ref/collection/WWIIScrp/id/1191>.
Note: These citations are programmatically generated and may be incomplete.