MLA

Kilpatrick, Jack Frederick (1915-1967). Unidentified note. Box 11, folder 983. undated. https://collections.library.yale.edu/catalog/15493787.

APA, 6th edition

Kilpatrick, Jack Frederick (1915-1967). (["Box 11, folder 983"])(undated)[Unidentified note]. https://collections.library.yale.edu/catalog/15493787.