MLA

Barrie, J. M. (James Matthew), 1860-1937. Birrell, Augustine. Box 16, folder 571. 1902. https://collections.library.yale.edu/catalog/2041659.

APA, 6th edition

Barrie, J. M. (James Matthew), 1860-1937. (["Box 16, folder 571"])(1902)[Birrell, Augustine]. https://collections.library.yale.edu/catalog/2041659.