MLA

Harriott, William Henry, -1839, artist. Cato Street Conspiracy : interior view of the secretary's room adjoining the hay loft where Thistlewood & the principal conspirators retreated on Ruthven, Smithers, & Ellis entering the loft on the night of Feb.y 23rd 1820. [Feb.] 26 1820.. https://collections.library.yale.edu/catalog/33300102.

APA, 6th edition

Harriott, William Henry, -1839, artist. ([Feb.] 26 1820.)[Cato Street Conspiracy : interior view of the secretary's room adjoining the hay loft where Thistlewood & the principal conspirators retreated on Ruthven, Smithers, & Ellis entering the loft on the night of Feb.y 23rd 1820]. https://collections.library.yale.edu/catalog/33300102.