MLA

Stieglitz, Alfred, 1864-1946. "Marsden [Hartley] Adopts Germany!," watercolor on paper. Box 158, folder 2908. 1913. https://collections.library.yale.edu/catalog/2017533.

APA, 6th edition

Stieglitz, Alfred, 1864-1946. (["Box 158, folder 2908"])(1913)["Marsden [Hartley] Adopts Germany!," watercolor on paper]. https://collections.library.yale.edu/catalog/2017533.