Não informado. Natural Resources & Energy. United Nations, Department of Technical Cooperation for Development.
Chicago-referens (17:e uppl.)Não informado. Natural Resources & Energy. New York: United Nations, Department of Technical Cooperation for Development.
MLA-referens (8:e uppl.)Não informado. Natural Resources & Energy. United Nations, Department of Technical Cooperation for Development.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.