MLA

Jordan, Viola Baxter, 1887-1973. Williams, William Carlos. Box 3, folder 106. 1936. https://collections.library.yale.edu/catalog/2038222.

APA, 6th edition

Jordan, Viola Baxter, 1887-1973. (["Box 3, folder 106"])(1936)[Williams, William Carlos]. https://collections.library.yale.edu/catalog/2038222.