*Raymond W. Goldsmith (1984), "An estimate of the size and structure of the national product of the Early Roman Empire", "Journal of the International Association for Research in Income and Wealth" 30*Bruce R. Gordon (2005).
* Raymond W. Goldsmith (1984), «An estimate of the size and structure of the national product of the Early Roman Empire», "Journal of the International Association for Research in Income and Wealth" 30* Bruce R. Gordon (2005).