MLA

Marinetti, F. T., 1876-1944. Handwritten letter from Gerardo Dottori to Marinetti, dated 6 marzo 1943, with signatures from Dottori's students. [10456-1]. box 131, slide 76. 1943. https://collections.library.yale.edu/catalog/10666682.

APA, 6th edition

Marinetti, F. T., 1876-1944. (["box 131, slide 76"])(1943)[Handwritten letter from Gerardo Dottori to Marinetti, dated 6 marzo 1943, with signatures from Dottori's students. [10456-1]]. https://collections.library.yale.edu/catalog/10666682.