Untitled [Self-addressed, stamped, postmarked envelope with New York Health and Racquet Club certificate inside]
MLA
Steinberg, Saul, 1914-1999. Untitled [Self-addressed, stamped, postmarked envelope with New York Health and Racquet Club certificate inside]. Box 76, folder 1448. 1984. https://collections.library.yale.edu/catalog/16855947.
APA, 6th edition
Steinberg, Saul, 1914-1999. (["Box 76, folder 1448"])(1984)[Untitled [Self-addressed, stamped, postmarked envelope with New York Health and Racquet Club certificate inside]]. https://collections.library.yale.edu/catalog/16855947.