MLA

Parkyns, George Isham, approximately 1750-approximately 1820, printmaker. Twickenham [graphic]. [1 December 1790]. https://collections.library.yale.edu/catalog/16035350.

APA, 6th edition

Parkyns, George Isham, approximately 1750-approximately 1820, printmaker. ([1 December 1790])[Twickenham [graphic]]. https://collections.library.yale.edu/catalog/16035350.