Cite

[Letter : 1967 February 20, Washington (D.C.), Smithsonian Institution to Saul Steinberg, Washington (D.C.)]

MLA

Institution, Smithsonian. [Letter : 1967 February 20, Washington (D.C.), Smithsonian Institution to Saul Steinberg, Washington (D.C.)]. 1967. https://collections.library.yale.edu/catalog/10058505.

APA, 6th edition

Institution, S. (1967). [Letter : 1967 February 20, Washington (D.C.), Smithsonian Institution to Saul Steinberg, Washington (D.C.)] [Correspondence, press releases (AAT)]. https://collections.library.yale.edu/catalog/10058505.