MLA

Trail, Ann Agnes, and artist. [Lady in a Bonnet] [Art Original]. 1821. https://collections.library.yale.edu/catalog/15815244.

APA, 6th edition

Trail, A. A., & artist. (1821). [Lady in a bonnet] [art original]. [Portraits British 18th century, Watercolors British 18th century, Paintings British 18th century]. https://collections.library.yale.edu/catalog/15815244.