MLA

Barrie, J. M. (James Matthew), 1860-1937. Brown, Curtis. Box 5, folder 83. 1935 October 29. https://collections.library.yale.edu/catalog/32312209.

APA, 6th edition

Barrie, J. M. (James Matthew), 1860-1937. (["Box 5, folder 83"])(1935 October 29)[Brown, Curtis]. https://collections.library.yale.edu/catalog/32312209.