Taagepera, Rein (1979). "Size and Duration of Empires: Growth-Decline Curves, 600 B.C. to 600 A.D.". Social Science History. 3 (3/4). p. 122. doi:10.2307/1170959. JSTOR1170959.
Taagepera, Rein (1979). "Size and Duration of Empires: Growth-Decline Curves, 600 B.C. to 600 A.D.". Social Science History. 3 (3/4). p. 122. doi:10.2307/1170959. JSTOR1170959.