MLA

Williams, William Carlos, 1883-1963. Witt-Diamant, Ruth. Box 26, folder 824. 1955-1960. https://collections.library.yale.edu/catalog/17049569.

APA, 6th edition

Williams, William Carlos, 1883-1963. (["Box 26, folder 824"])(1955-1960)[Witt-Diamant, Ruth]. https://collections.library.yale.edu/catalog/17049569.