MLA

Kilpatrick, Jack Frederick (1915-1967). Marion, Tom. Note. Box 8, folder 687. 1918 March 11. https://collections.library.yale.edu/catalog/15493041.

APA, 6th edition

Kilpatrick, Jack Frederick (1915-1967). (["Box 8, folder 687"])(1918 March 11)[Marion, Tom. Note]. https://collections.library.yale.edu/catalog/15493041.