MLA

A Peep at a Peer, or, The Guildford High Mettled Racer [Graphic]. publisher not identified, 0AD. https://collections.library.yale.edu/catalog/16816951.

APA, 6th edition

A peep at a peer, or, The Guildford high mettled racer [graphic]. (0 C.E.). [Caricatures and cartoons, Satires (Visual works) England 1821, Etchings England London 1821]. publisher not identified. https://collections.library.yale.edu/catalog/16816951.