MLA

Ely, William Davis, 1815-1908. Apthorp, Frances Louisa. Box 1, folder 1. 1845, 1847. https://collections.library.yale.edu/catalog/32532082.

APA, 6th edition

Ely, William Davis, 1815-1908. (["Box 1, folder 1"])(1845, 1847)[Apthorp, Frances Louisa]. https://collections.library.yale.edu/catalog/32532082.