Cite

German [mostly German military photographs]

MLA

Keller, Deane, 1901-1992. German [mostly German military photographs]. Box 34, folder 204. undated. https://collections.library.yale.edu/catalog/10468088.

APA, 6th edition

Keller, Deane, 1901-1992. (["Box 34, folder 204"])(undated)[German [mostly German military photographs]]. https://collections.library.yale.edu/catalog/10468088.