MLA

Sligo, Howe Peter Browne, Marquess of, 1788-1845. Letters to Marchioness Sligo. Box 1 | Folder 1. 1810. https://collections.library.yale.edu/catalog/16684071.

APA, 6th edition

Sligo, Howe Peter Browne, Marquess of, 1788-1845. (["Box 1 | Folder 1"])(1810)[Letters to Marchioness Sligo]. https://collections.library.yale.edu/catalog/16684071.