MLA

Steinberg, Saul, 1914-1999. Searle, Ronald, 1920-2011. Box 43, folder 776. 1950–1952. https://collections.library.yale.edu/catalog/2007968.

APA, 6th edition

Steinberg, Saul, 1914-1999. (["Box 43, folder 776"])(1950–1952)[Searle, Ronald, 1920-2011]. https://collections.library.yale.edu/catalog/2007968.