MLA

Steinberg, Saul, 1914-1999. Untitled [Faux certificate with red and blue seals; Figure with easel in landscape and faux calligraphy]. Box 78, folder 1540. undated. https://collections.library.yale.edu/catalog/32457124.

APA, 6th edition

Steinberg, Saul, 1914-1999. (["Box 78, folder 1540"])(undated)[Untitled [Faux certificate with red and blue seals; Figure with easel in landscape and faux calligraphy]]. https://collections.library.yale.edu/catalog/32457124.