Model 1917 American steel helmet

Chicago citation style
Model 1917 American steel helmet. 1917-1919. Retrieved from the Digital Public Library of America, http://cdm15138.contentdm.oclc.org/cdm/ref/collection/p15138coll29/id/1602. (Accessed October 20, 2019.)
APA citation style
(1917-1919) Model 1917 American steel helmet. Retrieved from the Digital Public Library of America, http://cdm15138.contentdm.oclc.org/cdm/ref/collection/p15138coll29/id/1602
MLA citation style
Retrieved from the Digital Public Library of America <http://cdm15138.contentdm.oclc.org/cdm/ref/collection/p15138coll29/id/1602>.
Note: These citations are programmatically generated and may be incomplete.