MLA

Brodsky, Joseph, 1940-1996. Unidentified fragments of poems by Brodsky, drafts. Box 69 | 1819-1831. undated. https://collections.library.yale.edu/catalog/17306157.

APA, 6th edition

Brodsky, Joseph, 1940-1996. (["Box 69 | 1819-1831"])(undated)[Unidentified fragments of poems by Brodsky, drafts]. https://collections.library.yale.edu/catalog/17306157.