MLA

MacDonald, George, 1824-1905. Arnold, Matthew. Box 1, folder 41. 1872 Mar 24. https://collections.library.yale.edu/catalog/16474486.

APA, 6th edition

MacDonald, George, 1824-1905. (["Box 1, folder 41"])(1872 Mar 24)[Arnold, Matthew]. https://collections.library.yale.edu/catalog/16474486.