MLA

Van Vechten, Carl, 1880-1964. Skibine, George, in Coppélia (probably), choreographed by Arthur Saint-Léon. Box 376, folder 5438. 1946 January 4. https://collections.library.yale.edu/catalog/10054090.

APA, 6th edition

Van Vechten, Carl, 1880-1964. (["Box 376, folder 5438"])(1946 January 4)[Skibine, George, in Coppélia (probably), choreographed by Arthur Saint-Léon]. https://collections.library.yale.edu/catalog/10054090.