United Nations. Statistical Office. (1974). World energy supplies, 1969-1972. United Nations.
Cita Chicago (17th ed.)United Nations. Statistical Office. World Energy Supplies, 1969-1972. New York: United Nations, 1974.
Cita MLA (9th ed.)United Nations. Statistical Office. World Energy Supplies, 1969-1972. United Nations, 1974.
Atenció: Aquestes cites poden no estar 100% correctes.