APA

Harkness G. E., . (1955). Foundations of Christian knowledge. New York: Abingdon Press.

Chicago

Harkness Georgia Elma, . 1955. Foundations of Christian knowledge. New York: Abingdon Press.

Harvard

Harkness G. E., . (1955). Foundations of Christian knowledge. New York: Abingdon Press.

MLA

Harkness Georgia Elma, . Foundations of Christian knowledge. New York: Abingdon Press. 1955.