MLA

Berberova, N. (Nina), 1901-1993. Baborenko, Aleksandr. Box 2, folder 39. 1966. https://collections.library.yale.edu/catalog/16687982.

APA, 6th edition

Berberova, N. (Nina), 1901-1993. (["Box 2, folder 39"])(1966)[Baborenko, Aleksandr]. https://collections.library.yale.edu/catalog/16687982.