MLA

Winslow, C.-E. A. (Charles-Edward Amory), 1877-1957. Winslow and others, Advisory Board, Anti-Epidemic Commission, League of Nations, Warsaw: 3 prints. Box 134, folder 73. 1921 April. https://collections.library.yale.edu/catalog/10015949.

APA, 6th edition

Winslow, C.-E. A. (Charles-Edward Amory), 1877-1957. (["Box 134, folder 73"])(1921 April)[Winslow and others, Advisory Board, Anti-Epidemic Commission, League of Nations, Warsaw: 3 prints]. https://collections.library.yale.edu/catalog/10015949.