International Monetary Fund. (1981). Direction of trade statistics. International Monetary Fund.
Cita Chicago (17th ed.)International Monetary Fund. Direction of Trade Statistics. Washington, D.C.: International Monetary Fund, 1981.
Cita MLA (8th ed.)International Monetary Fund. Direction of Trade Statistics. International Monetary Fund, 1981.
Atenció: Aquestes cites poden no estar 100% correctes.