MLA

Marinetti, F. T., 1876-1944. Anonymous. “Instrucciones para leer a los poetas ultraistas.” Grecia, 29 Feb 1920. [1477-1]. box 19, slide 57. 1920. https://collections.library.yale.edu/catalog/10650683.

APA, 6th edition

Marinetti, F. T., 1876-1944. (["box 19, slide 57"])(1920)[Anonymous. “Instrucciones para leer a los poetas ultraistas.” Grecia, 29 Feb 1920. [1477-1]]. https://collections.library.yale.edu/catalog/10650683.