MLA

Wheeler, Monroe, 1899-1988. Isherwood, Christopher. Box 5, folder 146. 1962. https://collections.library.yale.edu/catalog/17064454.

APA, 6th edition

Wheeler, Monroe, 1899-1988. (["Box 5, folder 146"])(1962)[Isherwood, Christopher]. https://collections.library.yale.edu/catalog/17064454.