MLA

Kilpatrick, Jack Frederick (1915-1967). Recto: Printed receipt from Tuel & Kincaid, Stilwell, Indian Territory; Verso: Documentation of a financial transaction. Box 6, folder 519. undated. https://collections.library.yale.edu/catalog/15492659.

APA, 6th edition

Kilpatrick, Jack Frederick (1915-1967). (["Box 6, folder 519"])(undated)[Recto: Printed receipt from Tuel & Kincaid, Stilwell, Indian Territory; Verso: Documentation of a financial transaction]. https://collections.library.yale.edu/catalog/15492659.