"B" general
MLA
MacDonald, George, 1824-1905. "B" general. Box 1, folder 42. 1862, 1880, n.d.. https://collections.library.yale.edu/catalog/17297713.
APA, 6th edition
MacDonald, George, 1824-1905. (["Box 1, folder 42"])(1862, 1880, n.d.)["B" general]. https://collections.library.yale.edu/catalog/17297713.