MLA

Stieglitz, Alfred, 1864-1946. Marsden Hartley. Box 124, folder 2474. [1911]. https://collections.library.yale.edu/catalog/2011585.

APA, 6th edition

Stieglitz, Alfred, 1864-1946. (["Box 124, folder 2474"])([1911])[Marsden Hartley]. https://collections.library.yale.edu/catalog/2011585.