: Peter Turchin, "Scientific Prediction in Historical Sociology: Ibn IChaldfin meets Al Saud." in Peter Turchin, Leonid Grinin, Andrae Korataev, and Victor C. de Munk. History and Mathematics: Historical Development of Complex Societies (Moscow, Kom Kniga, 2006); pp. 9-38; William R. Polk, "Encounters with Ibn Kha