Não informado. (2011). Annual Bulletin of Exports of Chemical Products. United Nations, Economic Commission for Europe.
Chicago-referens (17:e uppl.)Não informado. Annual Bulletin of Exports of Chemical Products. New York: United Nations, Economic Commission for Europe, 2011.
MLA-referens (8:e uppl.)Não informado. Annual Bulletin of Exports of Chemical Products. United Nations, Economic Commission for Europe, 2011.
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