MLA

Fitzgerald, Robert, 1910-1985. Fitts, Dudley. Box 12, folder 453-460. 1942-68. https://collections.library.yale.edu/catalog/17427371.

APA, 6th edition

Fitzgerald, Robert, 1910-1985. (["Box 12, folder 453-460"])(1942-68)[Fitts, Dudley]. https://collections.library.yale.edu/catalog/17427371.