MLA

Dennistoun, James, 1803-1855. Northesk, Georgiana Maria (Elliot) Carnegie, Countess of, 1811-1874. 5 ALS to Mrs. Dennistoun, Longwood and Ethie. Box 3, folder 135. 1847-48. https://collections.library.yale.edu/catalog/16683950.

APA, 6th edition

Dennistoun, James, 1803-1855. (["Box 3, folder 135"])(1847-48)[Northesk, Georgiana Maria (Elliot) Carnegie, Countess of, 1811-1874. 5 ALS to Mrs. Dennistoun, Longwood and Ethie]. https://collections.library.yale.edu/catalog/16683950.