MLA

Van Vechten, Carl, 1880-1964. Krutch, Joseph Wood. Box 385, folder 5785. 1937 May 30. https://collections.library.yale.edu/catalog/2055333.

APA, 6th edition

Van Vechten, Carl, 1880-1964. (["Box 385, folder 5785"])(1937 May 30)[Krutch, Joseph Wood]. https://collections.library.yale.edu/catalog/2055333.