MLA

Gillray, James, 1756-1815, printmaker. The pigs possessed, or, The broad bottom'd litter running headlong into [the] sea of perdition [graphic]. [18 April 1807]. https://collections.library.yale.edu/catalog/11858952.

APA, 6th edition

Gillray, James, 1756-1815, printmaker. ([18 April 1807])[The pigs possessed, or, The broad bottom'd litter running headlong into [the] sea of perdition [graphic]]. https://collections.library.yale.edu/catalog/11858952.