Cite

33. Man lying on ground with a machine gun.

MLA

Marinetti, F. T., 1876-1944. 33. Man lying on ground with a machine gun.. Box 49, folder 1939. ca. 1917. https://collections.library.yale.edu/catalog/2008597.

APA, 6th edition

Marinetti, F. T., 1876-1944. (["Box 49, folder 1939"])(ca. 1917)[33. Man lying on ground with a machine gun.]. https://collections.library.yale.edu/catalog/2008597.