APA

Kegley C. W., Bretall R. W. & Tillich P. (1956). Reinhold Niebuhr. New York: Macmillan Company.

Chicago

Kegley Charles W, Bretall Robert Walter and Tillich Paul. 1956. Reinhold Niebuhr. New York: Macmillan Company.

Harvard

Kegley C. W., Bretall R. W. and Tillich P. (1956). Reinhold Niebuhr. New York: Macmillan Company.

MLA

Kegley Charles W, Bretall Robert Walter and Tillich Paul. Reinhold Niebuhr. New York: Macmillan Company. 1956.