MLA

Stieglitz, Alfred, 1864-1946. Letters. Box 60, folder 1398-1407. 1917 Jul-Dec. https://collections.library.yale.edu/catalog/2038145.

APA, 6th edition

Stieglitz, Alfred, 1864-1946. (["Box 60, folder 1398-1407"])(1917 Jul-Dec)[Letters]. https://collections.library.yale.edu/catalog/2038145.