Bernie , F.(1981). Travels in the mongol Empire. Oxford University, London.
Floor, Willem. M. (2000). The Economy of Safavid Persia. Wiesbaden, Reichert.
Herbert , T. (1928). Travels in Persia 1627-1629. New edition, London.
North, Douglass C., Institution’s, Journal of Economic Perspective, Vol.5, No.2, 1991, p.97-112
North, D., J. Wallis., B. Weingast (2009). Violence and social order. Cambridge University Press, Cambridge.
Klein, Peter. G. (1999). New Institutional Economics: Encyclopedia of Law and Economic. In B. Boudewijn & Grrit De Geest. Edward Elgar, pp. 456-465.