MLA

Koch, Frederick R. (Frederick Robinson). Levine, David. Caricature of Proust: proof. Box 49, folder 1038. 1963. https://collections.library.yale.edu/catalog/16601858.

APA, 6th edition

Koch, Frederick R. (Frederick Robinson). (["Box 49, folder 1038"])(1963)[Levine, David. Caricature of Proust: proof]. https://collections.library.yale.edu/catalog/16601858.