MLA

Barrie, J. M. (James Matthew), 1860-1937. Frohman, Charles. Box 6, folder 188. 1906–1914. https://collections.library.yale.edu/catalog/32312240.

APA, 6th edition

Barrie, J. M. (James Matthew), 1860-1937. (["Box 6, folder 188"])(1906–1914)[Frohman, Charles]. https://collections.library.yale.edu/catalog/32312240.