MLA

Stieglitz, Alfred, 1864-1946. Letters. Box 80, folder 1651-52. 1946 Jun-Jul. https://collections.library.yale.edu/catalog/2046774.

APA, 6th edition

Stieglitz, Alfred, 1864-1946. (["Box 80, folder 1651-52"])(1946 Jun-Jul)[Letters]. https://collections.library.yale.edu/catalog/2046774.