MLA

Saarinen, Eero, 1910-1961. California: Death Valley. Box 12, folder 204. undated. https://collections.library.yale.edu/catalog/10020360.

APA, 6th edition

Saarinen, Eero, 1910-1961. (["Box 12, folder 204"])(undated)[California: Death Valley]. https://collections.library.yale.edu/catalog/10020360.