MLA

Kearny, Philip, 1815-1862. Letters, 1846. 1846 July 3. https://collections.library.yale.edu/catalog/9998715.

APA, 6th edition

Kearny, Philip, 1815-1862. (1846 July 3)[Letters, 1846]. https://collections.library.yale.edu/catalog/9998715.