Purkitt, H. E. (2007). Annual editions: World politics 06/07 (27th ed.). McGraw-Hill Contemporary Learning Series.
Dyfyniad Arddull ChicagoPurkitt, Helen E. Annual Editions: World Politics 06/07. 27th ed. Dubuque, Iowa: McGraw-Hill Contemporary Learning Series, 2007.
Dyfyniad MLAPurkitt, Helen E. Annual Editions: World Politics 06/07. 27th ed. McGraw-Hill Contemporary Learning Series, 2007.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.