Second scheme
MLA
Saarinen, Eero, 1910-1961. Second scheme. Box 571, folder 1588. undated. https://collections.library.yale.edu/catalog/10017260.
APA, 6th edition
Saarinen, Eero, 1910-1961. (["Box 571, folder 1588"])(undated)[Second scheme]. https://collections.library.yale.edu/catalog/10017260.