MLA

Turgenev, Ivan Sergeevich, 1818-1883. Letter : Saint-Valéry-sur-Somme, to Mrs. Benson. Box 28, folder GROUP 522, F-6. 1872 Aug 5. https://collections.library.yale.edu/catalog/32600878.

APA, 6th edition

Turgenev, Ivan Sergeevich, 1818-1883. (["Box 28, folder GROUP 522, F-6"])(1872 Aug 5)[Letter : Saint-Valéry-sur-Somme, to Mrs. Benson]. https://collections.library.yale.edu/catalog/32600878.