Einstein, William: correspondence
MLA
Stieglitz, Alfred, 1864-1946. Einstein, William: correspondence. Box 189, folder 3204-3209. 1936-58, n.d.. https://collections.library.yale.edu/catalog/32189149.
APA, 6th edition
Stieglitz, Alfred, 1864-1946. (["Box 189, folder 3204-3209"])(1936-58, n.d.)[Einstein, William: correspondence]. https://collections.library.yale.edu/catalog/32189149.