MLA

Saarinen, Eero, 1910-1961. Additional material. Box 676, folder 96. undated. https://collections.library.yale.edu/catalog/10021524.

APA, 6th edition

Saarinen, Eero, 1910-1961. (["Box 676, folder 96"])(undated)[Additional material]. https://collections.library.yale.edu/catalog/10021524.