MLA

Thayer, Scofield, 1889-1982. Butts, Mary. Box 1, folder 30. 1924-29. https://collections.library.yale.edu/catalog/31908784.

APA, 6th edition

Thayer, Scofield, 1889-1982. (["Box 1, folder 30"])(1924-29)[Butts, Mary]. https://collections.library.yale.edu/catalog/31908784.