Hanson, J. W., (2016), An Urban Geography of the Roman World, 100 B.C. to A.D. 300, (Oxford: Archaeopress). (This can be found here).
Hanson, J. W., (2011), ‘The urban system of Roman Asia Minor and wider connectivity’, in Bowman. A. K., and Wilson, A. I., (eds.), (2011), Settlement, Urbanization, and Population, Oxford Studies in the Roman Economy, (Oxford: Oxford University Press): 229-275. (This can be found here).