Dyfyniad APA
Turk, J. (1989). Introduction to environmental studies (3rd ed.). Saunders college.
Dyfyniad Arddull Chicago
Turk, Jonathan. Introduction to Environmental Studies. 3rd ed. Philadelphia: Saunders college, 1989.
Dyfyniad MLA
Turk, Jonathan. Introduction to Environmental Studies. 3rd ed. Saunders college, 1989.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.