APA aipamena

(2012). National Geographic Mei-Agustus 2012. Gramedia.

Chicago Style aipamena

National Geographic Mei-Agustus 2012. Gramedia, 2012.

MLA aipamena

National Geographic Mei-Agustus 2012. Gramedia, 2012.

Kontuz: berrikusi erreferentzia hauek erabili aurretik.