MLA

The Royal Ass [Graphic]. Pub accg. to act, May 20, 1780 by M Darly (39) Strand, 0AD. https://collections.library.yale.edu/catalog/10723406.

APA, 6th edition

The royal ass [graphic]. (0 C.E.). [Satires (Visual works) England 1780, Etchings England London 1780]. Pub accg. to act, May 20, 1780 by M Darly (39) Strand. https://collections.library.yale.edu/catalog/10723406.