"Sinclair Lewis"
MLA
Lewis, Sinclair, 1885-1951. "Sinclair Lewis". Box 70, folder 964. 1947. https://collections.library.yale.edu/catalog/17116565.
APA, 6th edition
Lewis, Sinclair, 1885-1951. (["Box 70, folder 964"])(1947)["Sinclair Lewis"]. https://collections.library.yale.edu/catalog/17116565.