APA

Keller H. A., . (1940). Let us have faith. New York: Doubleday, Doran & Co.

Chicago

Keller Helen Adams, . 1940. Let us have faith. New York: Doubleday, Doran & Co.

Harvard

Keller H. A., . (1940). Let us have faith. New York: Doubleday, Doran & Co.

MLA

Keller Helen Adams, . Let us have faith. New York: Doubleday, Doran & Co. 1940.