MLA

Serge, Victor, 1890-1947. Centre Americain Secours. Box 1, folder 13. 1942 Apr 11. https://collections.library.yale.edu/catalog/16495424.

APA, 6th edition

Serge, Victor, 1890-1947. (["Box 1, folder 13"])(1942 Apr 11)[Centre Americain Secours]. https://collections.library.yale.edu/catalog/16495424.