Cite

Thomas 6 Earl of Haddington [art original].

MLA

Thomas 6 Earl of Haddington [Art Original]. 0AD. https://collections.library.yale.edu/catalog/16193662.

APA, 6th edition

Thomas 6 Earl of Haddington [art original]. (0 C.E.). [Portraits, Portrait drawings, Watercolors British 19th century]. https://collections.library.yale.edu/catalog/16193662.