MLA

[Drawing of a Doorway with Cherub] [Art Original]. 0AD. https://collections.library.yale.edu/catalog/11019109.

APA, 6th edition

[Drawing of a doorway with cherub] [art original]. (0 C.E.). [Ink drawings British 18th century, Wash drawings British 18th century]. https://collections.library.yale.edu/catalog/11019109.