MLA

Schieffelin, Jacob, 1793-1880. Letter to her father John Lawrence, 1780 Dec 4 (typescript). Box 1, folder 2. n.d.. https://collections.library.yale.edu/catalog/16706046.

APA, 6th edition

Schieffelin, Jacob, 1793-1880. (["Box 1, folder 2"])(n.d.)[Letter to her father John Lawrence, 1780 Dec 4 (typescript)]. https://collections.library.yale.edu/catalog/16706046.