Empty envelopes
MLA
Whitman, Walt, 1819-1892. Empty envelopes. Box 2, folder 76. 1889, n.d.. https://collections.library.yale.edu/catalog/2053710.
APA, 6th edition
Whitman, Walt, 1819-1892. (["Box 2, folder 76"])(1889, n.d.)[Empty envelopes]. https://collections.library.yale.edu/catalog/2053710.