MLA

Emory, William H. (William Hemsley), 1811-1887. Correspondence. Box 4, folder 31. 1851 Jun-Jul. https://collections.library.yale.edu/catalog/2064401.

APA, 6th edition

Emory, William H. (William Hemsley), 1811-1887. (["Box 4, folder 31"])(1851 Jun-Jul)[Correspondence]. https://collections.library.yale.edu/catalog/2064401.