MLA

Pound, Ezra, 1885-1972. Hynes, Gladys. Box 1, folder 26. 1923-35. https://collections.library.yale.edu/catalog/17078440.

APA, 6th edition

Pound, Ezra, 1885-1972. (["Box 1, folder 26"])(1923-35)[Hynes, Gladys]. https://collections.library.yale.edu/catalog/17078440.