MLA

Steinberg, Saul, 1914-1999. Untitled [Man with hat and camera around neck; Woman seated in high-backed chair]. Box 80, folder 1789. undated. https://collections.library.yale.edu/catalog/16856356.

APA, 6th edition

Steinberg, Saul, 1914-1999. (["Box 80, folder 1789"])(undated)[Untitled [Man with hat and camera around neck; Woman seated in high-backed chair]]. https://collections.library.yale.edu/catalog/16856356.