MLA

Williams, William Carlos, 1883-1963. Miscellaneous writings, including notes on prescription pad. Box 65, folder 1376-1377. undated. https://collections.library.yale.edu/catalog/11870008.

APA, 6th edition

Williams, William Carlos, 1883-1963. (["Box 65, folder 1376-1377"])(undated)[Miscellaneous writings, including notes on prescription pad]. https://collections.library.yale.edu/catalog/11870008.