MLA

Ford, Charles Henri, 1908-2002. Lamantia, Philip. Box 1, folder 99. 1946 Mar 15. https://collections.library.yale.edu/catalog/17124855.

APA, 6th edition

Ford, Charles Henri, 1908-2002. (["Box 1, folder 99"])(1946 Mar 15)[Lamantia, Philip]. https://collections.library.yale.edu/catalog/17124855.