Winnifrith 1992, hlm. 54: "From about 1190 to 1216 there was the principality of Arbanon, which initially included most of the mountainous zones of Albania. After 1216 Arbanon was controlled successively by the Despotate of Epirus, by the Bulgarians, and from 1235 by the Byzantines in Nicaea." Winnifrith, Tom (1992). Perspectives On Albania (dalam bahasa Inggris). Springer. ISBN978-1-349-22050-2.
Clements 1992, hlm. 31: "By 1190, Byzantium's power had so receded that the archon Progon succeeded in establishing the first Albanian state of the Middle Ages, a principality." Clements, John (1992). Clements' Encyclopedia of World Governments. Vol. 10. Dallas, TX: Political Research, Incorporated.