MLA

Saarinen, Eero, 1910-1961. Exteriors. Box 168, folder 504. 1955-1963, undated. https://collections.library.yale.edu/catalog/10017733.

APA, 6th edition

Saarinen, Eero, 1910-1961. (["Box 168, folder 504"])(1955-1963, undated)[Exteriors]. https://collections.library.yale.edu/catalog/10017733.