MLA

Seligmann, Kurt, 1900-1962. Reiss family. Box 31. 1941-1942, undated. https://collections.library.yale.edu/catalog/17197916.

APA, 6th edition

Seligmann, Kurt, 1900-1962. (["Box 31"])(1941-1942, undated)[Reiss family]. https://collections.library.yale.edu/catalog/17197916.