MLA

Bonnor, Thomas, and artist printmaker. [Unidentified Monument] [Graphic]. publisher not identified, 0AD. https://collections.library.yale.edu/catalog/16194622.

APA, 6th edition

Bonnor, T., & printmaker, artist. (0 C.E.). [Unidentified monument] [graphic] [Engravings England London 1794, Watermarks (Paper) J. Whatman 1794]. publisher not identified. https://collections.library.yale.edu/catalog/16194622.