MLA

Kilpatrick, Jack Frederick (1915-1967). Unidentified note. Box 13, folder 1121. 1929 March 2. https://collections.library.yale.edu/catalog/15504943.

APA, 6th edition

Kilpatrick, Jack Frederick (1915-1967). (["Box 13, folder 1121"])(1929 March 2)[Unidentified note]. https://collections.library.yale.edu/catalog/15504943.