MLA

Acton, Harold, 1904-1994. Yuan Jiahua. Box 3, folder 177. 1939-1940. https://collections.library.yale.edu/catalog/17452758.

APA, 6th edition

Acton, Harold, 1904-1994. (["Box 3, folder 177"])(1939-1940)[Yuan Jiahua]. https://collections.library.yale.edu/catalog/17452758.