MLA

Pollard, Robert, 1755-1838, printmaker. Admiral Keppel [graphic]. [1779]. https://collections.library.yale.edu/catalog/10980007.

APA, 6th edition

Pollard, Robert, 1755-1838, printmaker. ([1779])[Admiral Keppel [graphic]]. https://collections.library.yale.edu/catalog/10980007.