MLA

Schwartz, Delmore, 1913-1966. "Modern Romance and Freedom". Box 6, folder 334. circa 1949. https://collections.library.yale.edu/catalog/32260770.

APA, 6th edition

Schwartz, Delmore, 1913-1966. (["Box 6, folder 334"])(circa 1949)["Modern Romance and Freedom"]. https://collections.library.yale.edu/catalog/32260770.