MLA

Stieglitz, Alfred, 1864-1946. "Seven Americans". Box 118, folder 2400. 1925. https://collections.library.yale.edu/catalog/17105677.

APA, 6th edition

Stieglitz, Alfred, 1864-1946. (["Box 118, folder 2400"])(1925)["Seven Americans"]. https://collections.library.yale.edu/catalog/17105677.