MLA

Morpurgo, Nelson, 1899-1978. "Incontro con Marinetti". Box 1, folder 11. n.d.. https://collections.library.yale.edu/catalog/2109178.

APA, 6th edition

Morpurgo, Nelson, 1899-1978. (["Box 1, folder 11"])(n.d.)["Incontro con Marinetti"]. https://collections.library.yale.edu/catalog/2109178.