MLA

Schwartz, Delmore, 1913-1966. Bay, Victoria. Box 1, folder 8. undated. https://collections.library.yale.edu/catalog/17078922.

APA, 6th edition

Schwartz, Delmore, 1913-1966. (["Box 1, folder 8"])(undated)[Bay, Victoria]. https://collections.library.yale.edu/catalog/17078922.