MLA

MacDonald, George, 1824-1905. Louisa MacDonald. Box 15, folder 411. 1856-85. https://collections.library.yale.edu/catalog/17297735.

APA, 6th edition

MacDonald, George, 1824-1905. (["Box 15, folder 411"])(1856-85)[Louisa MacDonald]. https://collections.library.yale.edu/catalog/17297735.