MLA

Emerson, Ralph Waldo, 1803-1882. Daguerreotype of Emerson. 37 (Art). undated. https://collections.library.yale.edu/catalog/11793106.

APA, 6th edition

Emerson, Ralph Waldo, 1803-1882. (["37 (Art)"])(undated)[Daguerreotype of Emerson]. https://collections.library.yale.edu/catalog/11793106.