MLA

Saarinen, Eero, 1910-1961. Exteriors. Box 158, folder 468. 1955, undated. https://collections.library.yale.edu/catalog/10017068.

APA, 6th edition

Saarinen, Eero, 1910-1961. (["Box 158, folder 468"])(1955, undated)[Exteriors]. https://collections.library.yale.edu/catalog/10017068.