MLA

Stieglitz, Alfred, 1864-1946. Letters. Box 77, folder 1610-1617. 1942 May-Nov. https://collections.library.yale.edu/catalog/2043832.

APA, 6th edition

Stieglitz, Alfred, 1864-1946. (["Box 77, folder 1610-1617"])(1942 May-Nov)[Letters]. https://collections.library.yale.edu/catalog/2043832.