MLA

Fitzgerald, Robert, 1910-1985. Houston, Peyton. Box 20, folder 716. 1935 Mar 5. https://collections.library.yale.edu/catalog/17093648.

APA, 6th edition

Fitzgerald, Robert, 1910-1985. (["Box 20, folder 716"])(1935 Mar 5)[Houston, Peyton]. https://collections.library.yale.edu/catalog/17093648.