MLA

Saarinen, Eero, 1910-1961. Sketches. Box 562, folder 1537. undated. https://collections.library.yale.edu/catalog/10013600.

APA, 6th edition

Saarinen, Eero, 1910-1961. (["Box 562, folder 1537"])(undated)[Sketches]. https://collections.library.yale.edu/catalog/10013600.