MLA

Palmquist, Peter E. (1936-2003). Widholm, Maria. Box 329, folder 2439. 1971-2003. https://collections.library.yale.edu/catalog/9998498.

APA, 6th edition

Palmquist, Peter E. (1936-2003). (["Box 329, folder 2439"])(1971-2003)[Widholm, Maria]. https://collections.library.yale.edu/catalog/9998498.