Diaghilev, Serge
MLA
Koch, Frederick R. (Frederick Robinson). Diaghilev, Serge. Box 51, folder 1087. 1917 Jan 12. https://collections.library.yale.edu/catalog/2065831.
APA, 6th edition
Koch, Frederick R. (Frederick Robinson). (["Box 51, folder 1087"])(1917 Jan 12)[Diaghilev, Serge]. https://collections.library.yale.edu/catalog/2065831.