MLA

Steinberg, Saul, 1914-1999. Untitled [Man in business suit seated in an armchair smoking and blowing smoke rings]. Box 414, folder 5531. undated. https://collections.library.yale.edu/catalog/16849913.

APA, 6th edition

Steinberg, Saul, 1914-1999. (["Box 414, folder 5531"])(undated)[Untitled [Man in business suit seated in an armchair smoking and blowing smoke rings]]. https://collections.library.yale.edu/catalog/16849913.