Ladewig Petersen, E. (1983) “Patricia Crone: Slaves on Horses. The Evolution of the Islamic Polity. Cambridge University Press, 1980. viii + 320 s. £ 17.50.”, Historisk Tidsskrift, 140. Tilgængelig hos: https://tidsskrift.dk/historisktidsskrift/article/view/52578 (Set: 11december2019).