MLA

Stepun, Fedor, 1884-1965. Leontovitsch, Victor. Box 20, folder 682. 1944-59. https://collections.library.yale.edu/catalog/16495063.

APA, 6th edition

Stepun, Fedor, 1884-1965. (["Box 20, folder 682"])(1944-59)[Leontovitsch, Victor]. https://collections.library.yale.edu/catalog/16495063.