MLA

Saarinen, Eero, 1910-1961. Exteriors. Box 566, folder 1540. undated. https://collections.library.yale.edu/catalog/10017348.

APA, 6th edition

Saarinen, Eero, 1910-1961. (["Box 566, folder 1540"])(undated)[Exteriors]. https://collections.library.yale.edu/catalog/10017348.