MLA

Williams, William Carlos, 1883-1963. Art Digest. Box 1, folder 27. 1954-1955. https://collections.library.yale.edu/catalog/17049446.

APA, 6th edition

Williams, William Carlos, 1883-1963. (["Box 1, folder 27"])(1954-1955)[Art Digest]. https://collections.library.yale.edu/catalog/17049446.