MLA

Thayer, Scofield, 1889-1982. Hofmannsthal, Hugo von. Box 34, folder 910-912. 1922-25. https://collections.library.yale.edu/catalog/17142316.

APA, 6th edition

Thayer, Scofield, 1889-1982. (["Box 34, folder 910-912"])(1922-25)[Hofmannsthal, Hugo von]. https://collections.library.yale.edu/catalog/17142316.