MLA

Lewis, Sinclair, 1885-1951. "Catalog of Dreams," poem. Box 35, folder 282. 1950 July. https://collections.library.yale.edu/catalog/17116519.

APA, 6th edition

Lewis, Sinclair, 1885-1951. (["Box 35, folder 282"])(1950 July)["Catalog of Dreams," poem]. https://collections.library.yale.edu/catalog/17116519.