MLA

Saarinen, Eero, 1910-1961. Additional material. Box 682, folder 142-144. undated. https://collections.library.yale.edu/catalog/10017625.

APA, 6th edition

Saarinen, Eero, 1910-1961. (["Box 682, folder 142-144"])(undated)[Additional material]. https://collections.library.yale.edu/catalog/10017625.