MLA

Stieglitz, Alfred, 1864-1946. Letters. Box 93, folder 1828-1835. 1942 Jul-Oct. https://collections.library.yale.edu/catalog/2044025.

APA, 6th edition

Stieglitz, Alfred, 1864-1946. (["Box 93, folder 1828-1835"])(1942 Jul-Oct)[Letters]. https://collections.library.yale.edu/catalog/2044025.