Cite

[Lady Mary Coke] [art original].

MLA

Harding, G. P. (George Perfect), 1780-1853, artist. [Lady Mary Coke] [art original].. [not after 1853]. https://collections.library.yale.edu/catalog/16704393.

APA, 6th edition

Harding, G. P. (George Perfect), 1780-1853, artist. ([not after 1853])[[Lady Mary Coke] [art original].]. https://collections.library.yale.edu/catalog/16704393.