APA

Longwell C. R., Flint R. F. & Knopf A. (1939). A textbook of geology. New York: J.Wiley & Sons.

Chicago

Longwell Chester R, Flint Richard F and Knopf Adolph. 1939. A textbook of geology. New York: J.Wiley & Sons.

Harvard

Longwell C. R., Flint R. F. and Knopf A. (1939). A textbook of geology. New York: J.Wiley & Sons.

MLA

Longwell Chester R, Flint Richard F and Knopf Adolph. A textbook of geology. New York: J.Wiley & Sons. 1939.