APA استشهاد

Lutgens, K. F., & Tarbuck, E. J. (1989). Essentials of geology/3rd ed (3rd ed.). Merrill.

استشهاد بنمط شيكاغو

Lutgens, K. Frederick, و Edward J. Tarbuck. Essentials of Geology/3rd Ed. 3rd ed. London: Merrill, 1989.

MLA استشهاد

Lutgens, K. Frederick, و Edward J. Tarbuck. Essentials of Geology/3rd Ed. 3rd ed. Merrill, 1989.