MLA

Stieglitz, Alfred, 1864-1946. Letters. Box 59, folder 1386-1397. 1917 Jan-Jun. https://collections.library.yale.edu/catalog/2038537.

APA, 6th edition

Stieglitz, Alfred, 1864-1946. (["Box 59, folder 1386-1397"])(1917 Jan-Jun)[Letters]. https://collections.library.yale.edu/catalog/2038537.