MLA

Thayer, Scofield, 1889-1982. Gregory, Alyse. Box 33, folder 868-890. 1920-34, n.d.. https://collections.library.yale.edu/catalog/11371425.

APA, 6th edition

Thayer, Scofield, 1889-1982. (["Box 33, folder 868-890"])(1920-34, n.d.)[Gregory, Alyse]. https://collections.library.yale.edu/catalog/11371425.