MLA

Kilpatrick, Jack Frederick (1915-1967). Unidentified note. Box 8, folder 694. 1908 July 31. https://collections.library.yale.edu/catalog/15493042.

APA, 6th edition

Kilpatrick, Jack Frederick (1915-1967). (["Box 8, folder 694"])(1908 July 31)[Unidentified note]. https://collections.library.yale.edu/catalog/15493042.