MLA

Marinetti, F. T., 1876-1944. Anonymous. "La conferenza Marinetti al Circolo Artistico." No source, [1931]. [6855-1]. box 86, slide 75. 1931. https://collections.library.yale.edu/catalog/10659521.

APA, 6th edition

Marinetti, F. T., 1876-1944. (["box 86, slide 75"])(1931)[Anonymous. "La conferenza Marinetti al Circolo Artistico." No source, [1931]. [6855-1]]. https://collections.library.yale.edu/catalog/10659521.