Jabarkan Nota dari Raja Rom dalam bahasa melayu

This article uses material translated from the corresponding article in the German-language Wikipedia, which, in turn, cites a source that contains further references:

H. Beumann: Rex Romanorum, in: Lexikon des Mittelalters (Dictionary of the Middle Ages, 9 vols., Munich-Zurich 1980-98), vol. 7, col. 777 f.