MLA

Whitman, Walt, 1819-1892. Holograph manuscript, corrected. Box 3, folder 112. 1890 Aug 4. https://collections.library.yale.edu/catalog/2053746.

APA, 6th edition

Whitman, Walt, 1819-1892. (["Box 3, folder 112"])(1890 Aug 4)[Holograph manuscript, corrected]. https://collections.library.yale.edu/catalog/2053746.