Cite

[Two ladies with a picnic basket] [art original].

MLA

Beauclerk, Diana, Lady, 1734-1808, artist. [Two ladies with a picnic basket] [art original].. [between 1770 and 1808]. https://collections.library.yale.edu/catalog/11138718.

APA, 6th edition

Beauclerk, Diana, Lady, 1734-1808, artist. ([between 1770 and 1808])[[Two ladies with a picnic basket] [art original].]. https://collections.library.yale.edu/catalog/11138718.