MLA

Steinberg, Saul, 1914-1999. Untitled [Monkey dressed in Ritz bellboy uniform with cat woman in frilled collar]. Box 463, folder 6437. circa 1987. https://collections.library.yale.edu/catalog/16851529.

APA, 6th edition

Steinberg, Saul, 1914-1999. (["Box 463, folder 6437"])(circa 1987)[Untitled [Monkey dressed in Ritz bellboy uniform with cat woman in frilled collar]]. https://collections.library.yale.edu/catalog/16851529.