430. Mt. Etna. Postcard.
MLA
Marinetti, F. T., 1876-1944. 430. Mt. Etna. Postcard.. Box 52, folder 1969. n.d.. https://collections.library.yale.edu/catalog/2009481.
APA, 6th edition
Marinetti, F. T., 1876-1944. (["Box 52, folder 1969"])(n.d.)[430. Mt. Etna. Postcard.]. https://collections.library.yale.edu/catalog/2009481.