MLA

Berberova, N. (Nina), 1901-1993. Merezhkovsky, Dmitry Sergeyevich. Box 14, folder 392. 1926 Jul 26. https://collections.library.yale.edu/catalog/16688021.

APA, 6th edition

Berberova, N. (Nina), 1901-1993. (["Box 14, folder 392"])(1926 Jul 26)[Merezhkovsky, Dmitry Sergeyevich]. https://collections.library.yale.edu/catalog/16688021.