Peter Jay, Road to Riches or The Wealth of Man (London, 2000), pp. 205–36; Gerhard E. Lenski, Power and Privilege: A Theory of Social Stratification (Chapel Hill and London, 1966), pp. 297–392; Marshall G. S. Hodgson, The Venture of Islam: Conscience and History in a World Civilization, 3 vols (Chicago and London, 1974), 3, pp. 195–201