Taagepera, Rein (1979). „Size and Duration of Empires: Growth-Decline Curves, 600 B.C. to 600 A.D.”. Social Science History. 3 (3/4): 117. JSTOR1170959. doi:10.2307/1170959.
Taagepera, Rein (1979). „Size and Duration of Empires: Growth-Decline Curves, 600 B.C. to 600 A.D.”. Social Science History. 3 (3/4): 117. JSTOR1170959. doi:10.2307/1170959.
„empire”. The Free Dictionary. Приступљено 26. 10. 2018. „any monarchy that for reasons of history, prestige, etc, has an emperor rather than a king as head of state”