MLA

Lewis, Sinclair, 1885-1951. Rolland, Romain. Box 48, folder 597. 1935. https://collections.library.yale.edu/catalog/17116548.

APA, 6th edition

Lewis, Sinclair, 1885-1951. (["Box 48, folder 597"])(1935)[Rolland, Romain]. https://collections.library.yale.edu/catalog/17116548.