MLA

Harding, G. P. (George Perfect), 1780-1853, artist. [Medal of Queen Mary of England and King Philip II of Spain] [art original].. [not after 1824]. https://collections.library.yale.edu/catalog/16193451.

APA, 6th edition

Harding, G. P. (George Perfect), 1780-1853, artist. ([not after 1824])[[Medal of Queen Mary of England and King Philip II of Spain] [art original].]. https://collections.library.yale.edu/catalog/16193451.