World Bank. (1989). Price prospects for major primary commodities, 1988-2000. World Bank.
Cita Chicago (17th ed.)World Bank. Price Prospects for Major Primary Commodities, 1988-2000. Washington, D.C.: World Bank, 1989.
Cita MLA (8th ed.)World Bank. Price Prospects for Major Primary Commodities, 1988-2000. World Bank, 1989.
Atenció: Aquestes cites poden no estar 100% correctes.