MLA

Vernier, Charles, 1831-1887, printmaker. La polka-morbus [graphic]. [ca. 1845]. https://collections.library.yale.edu/catalog/17339682.

APA, 6th edition

Vernier, Charles, 1831-1887, printmaker. ([ca. 1845])[La polka-morbus [graphic]]. https://collections.library.yale.edu/catalog/17339682.