Purkitt, H. E. (2007). Annual editions: World politics 06/07 (27th ed.). McGraw-Hill Contemporary Learning Series.
Chicago Style aipamenaPurkitt, Helen E. Annual Editions: World Politics 06/07. 27th ed. Dubuque, Iowa: McGraw-Hill Contemporary Learning Series, 2007.
MLA aipamenaPurkitt, Helen E. Annual Editions: World Politics 06/07. 27th ed. McGraw-Hill Contemporary Learning Series, 2007.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.