Cite

Letter signed. 2 1/2 pages, folio. Philadelphia.

MLA

family, Rochambeau. Letter Signed. 2 1/2 Pages, Folio. Philadelphia. 1780. https://collections.library.yale.edu/catalog/16490983.

APA, 6th edition

family, R. (1780). Letter signed. 2 1/2 pages, folio. Philadelphia. https://collections.library.yale.edu/catalog/16490983.