MLA

Harding, G. P. (George Perfect), 1780-1853, artist. Lady Bellasis [art original].. [ca. 1805]. https://collections.library.yale.edu/catalog/16704417.

APA, 6th edition

Harding, G. P. (George Perfect), 1780-1853, artist. ([ca. 1805])[Lady Bellasis [art original].]. https://collections.library.yale.edu/catalog/16704417.