MLA

Emory, William H. (William Hemsley), 1811-1887. Correspondence. Box 4, folder 23. 1850 Jan. https://collections.library.yale.edu/catalog/16686612.

APA, 6th edition

Emory, William H. (William Hemsley), 1811-1887. (["Box 4, folder 23"])(1850 Jan)[Correspondence]. https://collections.library.yale.edu/catalog/16686612.