MLA

Knock out This Enemy Don't Be a Casualty to Venereal Disease ... [Graphic]. Venereal Disease Education Institute, 0AD. https://collections.library.yale.edu/catalog/16047169.

APA, 6th edition

Knock out this enemy Don't be a casualty to Venereal Disease ... [graphic]. (0 C.E.). [Posters, War posters, Offset lithographs]. Venereal Disease Education Institute. https://collections.library.yale.edu/catalog/16047169.