APA

Pennington L. A., Berg I. A., . (1948). An introduction to clinical psychology. New York: Ronald Press Co.

Chicago

Pennington Leon Alfred, Berg Irwin August, . 1948. An introduction to clinical psychology. New York: Ronald Press Co.

Harvard

Pennington L. A., Berg I. A., . (1948). An introduction to clinical psychology. New York: Ronald Press Co.

MLA

Pennington Leon Alfred, Berg Irwin August, . An introduction to clinical psychology. New York: Ronald Press Co. 1948.