MLA

Kilpatrick, Jack Frederick (1915-1967). Wadi, Henili (Watt, Henry). Business letter beginning "ayvno nasgwo adela digvginedi ugvwali". Box 7, folder 591. undated. https://collections.library.yale.edu/catalog/15492890.

APA, 6th edition

Kilpatrick, Jack Frederick (1915-1967). (["Box 7, folder 591"])(undated)[Wadi, Henili (Watt, Henry). Business letter beginning "ayvno nasgwo adela digvginedi ugvwali"]. https://collections.library.yale.edu/catalog/15492890.