MLA

Williams, William Carlos, 1883-1963. Shakespeare and Company. Box 21, folder 673. 1928-1939. https://collections.library.yale.edu/catalog/17049545.

APA, 6th edition

Williams, William Carlos, 1883-1963. (["Box 21, folder 673"])(1928-1939)[Shakespeare and Company]. https://collections.library.yale.edu/catalog/17049545.