MLA

Marinetti, F. T., 1876-1944. 197. Sofia, Bulgaria. FTM and BCM in a group. Inscribed on verso: "a Sofia Dicembre [sic] 1932.". Box 50, folder 1949. 1932 Jan. https://collections.library.yale.edu/catalog/2008926.

APA, 6th edition

Marinetti, F. T., 1876-1944. (["Box 50, folder 1949"])(1932 Jan)[197. Sofia, Bulgaria. FTM and BCM in a group. Inscribed on verso: "a Sofia Dicembre [sic] 1932."]. https://collections.library.yale.edu/catalog/2008926.