MLA

Saarinen, Eero, 1910-1961. Model. Box 169, folder 507. undated. https://collections.library.yale.edu/catalog/10017572.

APA, 6th edition

Saarinen, Eero, 1910-1961. (["Box 169, folder 507"])(undated)[Model]. https://collections.library.yale.edu/catalog/10017572.