United Nations Economic Commission for Europe. (1979). The Gas Situation in the ECE Region Around the Year 1990. ELSEVIER.
Chicago-viite (17. p.)United Nations Economic Commission for Europe. The Gas Situation in the ECE Region Around the Year 1990. ELSEVIER, 1979.
MLA-viite (8. p.)United Nations Economic Commission for Europe. The Gas Situation in the ECE Region Around the Year 1990. ELSEVIER, 1979.
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