MLA

Berberova, N. (Nina), 1901-1993. Nappelbaum, Ida. Box 15, folder 411. 1968-92, n.d.. https://collections.library.yale.edu/catalog/17305287.

APA, 6th edition

Berberova, N. (Nina), 1901-1993. (["Box 15, folder 411"])(1968-92, n.d.)[Nappelbaum, Ida]. https://collections.library.yale.edu/catalog/17305287.