International Monetary Fund. Statistics Dept. (1981). Direction of Trade Statistics Yearbook, 1981 Edition. International Monetary Fund.
Chicago-referens (17:e uppl.)International Monetary Fund. Statistics Dept. Direction of Trade Statistics Yearbook, 1981 Edition. Washington, D.C.: International Monetary Fund, 1981.
MLA-referens (8:e uppl.)International Monetary Fund. Statistics Dept. Direction of Trade Statistics Yearbook, 1981 Edition. International Monetary Fund, 1981.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.