MLA

Ass upon Ass [Graphic]. Pub. by HHumphrey, No. 18 New Bond Strt, 0AD. https://collections.library.yale.edu/catalog/10723431.

APA, 6th edition

Ass upon ass [graphic]. (0 C.E.). [Satires (Visual works) England 1780, Etchings England London 1780]. Pub. by HHumphrey, No. 18 New Bond Strt. https://collections.library.yale.edu/catalog/10723431.