MLA

Kilpatrick, Jack Frederick (1915-1967). Washington, George. Letter to Jack Kilpatrick in Cherokee and English and envelope. Box 22, folder 1826. 1963 August 26. https://collections.library.yale.edu/catalog/15532630.

APA, 6th edition

Kilpatrick, Jack Frederick (1915-1967). (["Box 22, folder 1826"])(1963 August 26)[Washington, George. Letter to Jack Kilpatrick in Cherokee and English and envelope]. https://collections.library.yale.edu/catalog/15532630.