MLA

Benét, Stephen Vincent, 1898-1943. Pearson, Norman Holmes. Box 23, folder 943. 1948-1962, undated. https://collections.library.yale.edu/catalog/10167563.

APA, 6th edition

Benét, Stephen Vincent, 1898-1943. (["Box 23, folder 943"])(1948-1962, undated)[Pearson, Norman Holmes]. https://collections.library.yale.edu/catalog/10167563.