MLA

Marinetti, F. T., 1876-1944. Page full of signatures: Marinetti, Ungaretti, Illari, etc. No source. [8406-1]. box 106, slide 26. no date. https://collections.library.yale.edu/catalog/10662528.

APA, 6th edition

Marinetti, F. T., 1876-1944. (["box 106, slide 26"])(no date)[Page full of signatures: Marinetti, Ungaretti, Illari, etc. No source. [8406-1]]. https://collections.library.yale.edu/catalog/10662528.