MLA

Marinetti, F. T., 1876-1944. Francesco Cangiullo. No title. No source, 1923. Verso of "Poesia pentagrammata." [2966-1]. box 38, slide 26. 1923. https://collections.library.yale.edu/catalog/10653318.

APA, 6th edition

Marinetti, F. T., 1876-1944. (["box 38, slide 26"])(1923)[Francesco Cangiullo. No title. No source, 1923. Verso of "Poesia pentagrammata." [2966-1]]. https://collections.library.yale.edu/catalog/10653318.