MLA

Williams, William Carlos, 1883-1963. The Grecourt Review. Box 7, folder 246. 1957. https://collections.library.yale.edu/catalog/17049482.

APA, 6th edition

Williams, William Carlos, 1883-1963. (["Box 7, folder 246"])(1957)[The Grecourt Review]. https://collections.library.yale.edu/catalog/17049482.