MLA

Saarinen, Eero, 1910-1961. Early sketches. Box 568, folder 1563. [1959]. https://collections.library.yale.edu/catalog/10017361.

APA, 6th edition

Saarinen, Eero, 1910-1961. (["Box 568, folder 1563"])([1959])[Early sketches]. https://collections.library.yale.edu/catalog/10017361.