Purkitt, H. E. (2007). Annual editions: World politics 06/07 (27th ed.). McGraw-Hill Contemporary Learning Series.
Chicago-referens (17:e uppl.)Purkitt, Helen E. Annual Editions: World Politics 06/07. 27th ed. Dubuque, Iowa: McGraw-Hill Contemporary Learning Series, 2007.
MLA-referens (8:e uppl.)Purkitt, Helen E. Annual Editions: World Politics 06/07. 27th ed. McGraw-Hill Contemporary Learning Series, 2007.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.