MLA

Hale, Sarah Josepha Buell, 1788-1879. Letter : Phila[delphia], to Miss Lynch. Box 34, folder GROUP 556, F-2. 1851 March 6. https://collections.library.yale.edu/catalog/17432535.

APA, 6th edition

Hale, Sarah Josepha Buell, 1788-1879. (["Box 34, folder GROUP 556, F-2"])(1851 March 6)[Letter : Phila[delphia], to Miss Lynch]. https://collections.library.yale.edu/catalog/17432535.