MLA

Stieglitz, Alfred, 1864-1946. Letters. Box 74, folder 1567. 1937 Jan. https://collections.library.yale.edu/catalog/2042634.

APA, 6th edition

Stieglitz, Alfred, 1864-1946. (["Box 74, folder 1567"])(1937 Jan)[Letters]. https://collections.library.yale.edu/catalog/2042634.