MLA

Geldzahler, Henry, 1935-1994. "6 Young Unknown Artists": 2 page original typescript with author corrections, for exhibition at DIA Art Foundation in Bridgehampton, NY. Box 1, folder 27. circa 1987. https://collections.library.yale.edu/catalog/10082357.

APA, 6th edition

Geldzahler, Henry, 1935-1994. (["Box 1, folder 27"])(circa 1987)["6 Young Unknown Artists": 2 page original typescript with author corrections, for exhibition at DIA Art Foundation in Bridgehampton, NY]. https://collections.library.yale.edu/catalog/10082357.