MLA

Johnson, James Weldon, 1871-1938. Van Vechten, Carl. Box 37, folder 240. 1940-42. https://collections.library.yale.edu/catalog/2003337.

APA, 6th edition

Johnson, James Weldon, 1871-1938. (["Box 37, folder 240"])(1940-42)[Van Vechten, Carl]. https://collections.library.yale.edu/catalog/2003337.