MLA

Schwartz, Delmore, 1913-1966. "An American Dream". Box 4, folder 252-253. circa 1956. https://collections.library.yale.edu/catalog/32260527.

APA, 6th edition

Schwartz, Delmore, 1913-1966. (["Box 4, folder 252-253"])(circa 1956)["An American Dream"]. https://collections.library.yale.edu/catalog/32260527.