MLA

Steinberg, Saul, 1914-1999. Inventory. Box 367, folder 4902. undated. https://collections.library.yale.edu/catalog/16857124.

APA, 6th edition

Steinberg, Saul, 1914-1999. (["Box 367, folder 4902"])(undated)[Inventory]. https://collections.library.yale.edu/catalog/16857124.