MLA

Van Vechten, Carl, 1880-1964. Zaidins, Earle Warren. Box 49, folder 944. 1958 December 10. https://collections.library.yale.edu/catalog/32190530.

APA, 6th edition

Van Vechten, Carl, 1880-1964. (["Box 49, folder 944"])(1958 December 10)[Zaidins, Earle Warren]. https://collections.library.yale.edu/catalog/32190530.