MLA

Morse, Samuel Finley Breese, 1791-1872. Key to Morse's picture of the House of representatives / [signed Saml. F. B. Morse, New Haven, Feb. 1st, 1823].. 1823]. https://collections.library.yale.edu/catalog/11867794.

APA, 6th edition

Morse, Samuel Finley Breese, 1791-1872. (1823])[Key to Morse's picture of the House of representatives / [signed Saml. F. B. Morse, New Haven, Feb. 1st, 1823].]. https://collections.library.yale.edu/catalog/11867794.