MLA

Seligmann, Kurt, 1900-1962. Schapiro, Meyer. Box 31. 1941-1949, undated. https://collections.library.yale.edu/catalog/17197917.

APA, 6th edition

Seligmann, Kurt, 1900-1962. (["Box 31"])(1941-1949, undated)[Schapiro, Meyer]. https://collections.library.yale.edu/catalog/17197917.