APA (7th ed.) Zitazioa
O'Brien Derek. (2004). Gk with derek the ultimate general knowledge and quiz compendium: 3 science and wildlife. Penguin Books.
Chicago Style (17th ed.) Zitazioa
O'Brien Derek. Gk with Derek the Ultimate General Knowledge and Quiz Compendium: 3 Science and Wildlife. New Delhi: Penguin Books, 2004.
MLA (9th ed.) Zitazioa
O'Brien Derek. Gk with Derek the Ultimate General Knowledge and Quiz Compendium: 3 Science and Wildlife. Penguin Books, 2004.
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