Simpson, Helen; Simpson, Kenneth; Simpson, William Kelly
MLA
Stein, Gertrude, 1874-1946. Simpson, Helen; Simpson, Kenneth; Simpson, William Kelly. Box 124, folder 2690. 1934-38, n.d.. https://collections.library.yale.edu/catalog/10186953.
APA, 6th edition
Stein, Gertrude, 1874-1946. (["Box 124, folder 2690"])(1934-38, n.d.)[Simpson, Helen; Simpson, Kenneth; Simpson, William Kelly]. https://collections.library.yale.edu/catalog/10186953.