MLA

[Portrait of George Griffith] [Art Original]. 0AD. https://collections.library.yale.edu/catalog/11138655.

APA, 6th edition

[Portrait of George Griffith] [art original]. (0 C.E.). [Ink drawings British 18th century, Wash drawings British 18th century, Watermarks (Paper) J Whatman]. https://collections.library.yale.edu/catalog/11138655.