Jahrhundert" (Oldenbourg Wissenschaftsverlag 1999, ISBN 3-486-56385-8, S. 18) (restricted online version (Google Books))*Fred Singleton, Frederick Bernard Singleton: "A Short History of the Yugoslav Peoples".
Jahrhundert" (Oldenbourg Wissenschaftsverlag 1999, ISBN 3486563858, S. 18) (restricted online version (Google Books))* Fred Singleton, Frederick Bernard Singleton: "A Short History of the Yugoslav Peoples".