MLA

Whitman, Walt, 1819-1892. "Walt Whitman's Poem To-day at Dartmouth College," holograph manuscript, corrected. Box 3, folder 118. [1872?] Jun 26. https://collections.library.yale.edu/catalog/2053752.

APA, 6th edition

Whitman, Walt, 1819-1892. (["Box 3, folder 118"])([1872?] Jun 26)["Walt Whitman's Poem To-day at Dartmouth College," holograph manuscript, corrected]. https://collections.library.yale.edu/catalog/2053752.