MLA

Barrie, J. M. (James Matthew), 1860-1937. Boucicault, Nina. Box 4, folder 68. 1910. https://collections.library.yale.edu/catalog/32312202.

APA, 6th edition

Barrie, J. M. (James Matthew), 1860-1937. (["Box 4, folder 68"])(1910)[Boucicault, Nina]. https://collections.library.yale.edu/catalog/32312202.