MLA

Kilpatrick, Jack Frederick (1915-1967). Unidentified note. Box 13, folder 1138. undated. https://collections.library.yale.edu/catalog/15515934.

APA, 6th edition

Kilpatrick, Jack Frederick (1915-1967). (["Box 13, folder 1138"])(undated)[Unidentified note]. https://collections.library.yale.edu/catalog/15515934.