MLA

Stieglitz, Alfred, 1864-1946. "Standing Nude". Box 130, folder 2508. ca. 1915. https://collections.library.yale.edu/catalog/2002547.

APA, 6th edition

Stieglitz, Alfred, 1864-1946. (["Box 130, folder 2508"])(ca. 1915)["Standing Nude"]. https://collections.library.yale.edu/catalog/2002547.