Portfolio Two: Sheets 26-56
MLA
Stieglitz, Alfred, 1864-1946. Portfolio Two: Sheets 26-56. Box 116 (Oversize). 1908-36, n.d.. https://collections.library.yale.edu/catalog/10732809.
APA, 6th edition
Stieglitz, Alfred, 1864-1946. (["Box 116 (Oversize)"])(1908-36, n.d.)[Portfolio Two: Sheets 26-56]. https://collections.library.yale.edu/catalog/10732809.