MLA

Stieglitz, Alfred, 1864-1946. Pemberton, Murdock. Box 208, folder 3626. 1950. https://collections.library.yale.edu/catalog/2112238.

APA, 6th edition

Stieglitz, Alfred, 1864-1946. (["Box 208, folder 3626"])(1950)[Pemberton, Murdock]. https://collections.library.yale.edu/catalog/2112238.