MLA

DeWitt, Miriam Hapgood, 1906-1990. Hapgood family. Box 6, folder 60. 1902, undated. https://collections.library.yale.edu/catalog/2008565.

APA, 6th edition

DeWitt, Miriam Hapgood, 1906-1990. (["Box 6, folder 60"])(1902, undated)[Hapgood family]. https://collections.library.yale.edu/catalog/2008565.