MLA

Stieglitz, Alfred, 1864-1946. Letters. Box 70, folder 1519-1525. 1933 Jul-Dec. https://collections.library.yale.edu/catalog/2041340.

APA, 6th edition

Stieglitz, Alfred, 1864-1946. (["Box 70, folder 1519-1525"])(1933 Jul-Dec)[Letters]. https://collections.library.yale.edu/catalog/2041340.