MLA

Serge, Victor, 1890-1947. Workers Defense League. Box 2, folder 88. 1942 Mar 20. https://collections.library.yale.edu/catalog/17455292.

APA, 6th edition

Serge, Victor, 1890-1947. (["Box 2, folder 88"])(1942 Mar 20)[Workers Defense League]. https://collections.library.yale.edu/catalog/17455292.