United Nations Conference On Trade And Development. (1991). UNCTAD Commodity Yearbook 1991. United Nations.
Цитирование в стиле Чикаго (17-е изд.)United Nations Conference On Trade And Development. UNCTAD Commodity Yearbook 1991. New York: United Nations, 1991.
Цитирование MLA (8-е изд.)United Nations Conference On Trade And Development. UNCTAD Commodity Yearbook 1991. United Nations, 1991.
Предупреждение: эти цитированмия не могут быть всегда правильны на 100%.