Cite

Standingdeer, Dave. letter, 4 pages

MLA

Kilpatrick, Jack Frederick (1915-1967). Standingdeer, Dave. letter, 4 pages. Box 2, folder 120. undated. https://collections.library.yale.edu/catalog/15492268.

APA, 6th edition

Kilpatrick, Jack Frederick (1915-1967). (["Box 2, folder 120"])(undated)[Standingdeer, Dave. letter, 4 pages]. https://collections.library.yale.edu/catalog/15492268.