MLA

Stieglitz, Alfred, 1864-1946. Letters. Box 92, folder 1825-1827. 1942 May-Jun. https://collections.library.yale.edu/catalog/2043719.

APA, 6th edition

Stieglitz, Alfred, 1864-1946. (["Box 92, folder 1825-1827"])(1942 May-Jun)[Letters]. https://collections.library.yale.edu/catalog/2043719.