APA (7th ed.) Zitazioa
Turk, J. (1989). Introduction to environmental studies (3rd ed.). Saunders college.
Chicago Style (17th ed.) Zitazioa
Turk, Jonathan. Introduction to Environmental Studies. 3rd ed. Philadelphia: Saunders college, 1989.
MLA (9th ed.) Zitazioa
Turk, Jonathan. Introduction to Environmental Studies. 3rd ed. Saunders college, 1989.
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