MLA

Marinetti, F. T., 1876-1944. Enrico Prampolini. No title, No source About German and Italian theatre. [9330-1]. box 117, slide 70. no date. https://collections.library.yale.edu/catalog/10664232.

APA, 6th edition

Marinetti, F. T., 1876-1944. (["box 117, slide 70"])(no date)[Enrico Prampolini. No title, No source About German and Italian theatre. [9330-1]]. https://collections.library.yale.edu/catalog/10664232.