MLA

Whitman, Walt, 1819-1892. Galley proof, corrected. Box 3, folder 156. 1889 Nov. https://collections.library.yale.edu/catalog/2007251.

APA, 6th edition

Whitman, Walt, 1819-1892. (["Box 3, folder 156"])(1889 Nov)[Galley proof, corrected]. https://collections.library.yale.edu/catalog/2007251.