MLA

Van Vechten, Carl, 1880-1964. Anderson, Judith, probably as Napoleon II of France, Duke of Reichstadt, in L'Aiglon, by Edmond Rostand. Box 332, folder 4120. 1941 May 26. https://collections.library.yale.edu/catalog/2029812.

APA, 6th edition

Van Vechten, Carl, 1880-1964. (["Box 332, folder 4120"])(1941 May 26)[Anderson, Judith, probably as Napoleon II of France, Duke of Reichstadt, in L'Aiglon, by Edmond Rostand]. https://collections.library.yale.edu/catalog/2029812.