MLA

Stieglitz, Alfred, 1864-1946. Letters. Box 94, folder 1846. 1944 Apr-Jul. https://collections.library.yale.edu/catalog/2044263.

APA, 6th edition

Stieglitz, Alfred, 1864-1946. (["Box 94, folder 1846"])(1944 Apr-Jul)[Letters]. https://collections.library.yale.edu/catalog/2044263.