MLA

Pound, Ezra, 1885-1972. Sonnets: autograph ms.. Box 80, folder 3547. [1910]. https://collections.library.yale.edu/catalog/17430564.

APA, 6th edition

Pound, Ezra, 1885-1972. (["Box 80, folder 3547"])([1910])[Sonnets: autograph ms.]. https://collections.library.yale.edu/catalog/17430564.