Não informado. (1956). Half-yearly Bulletin of Electric Energy Statistics for Europe. United Nations, Economic Commission for Europe.
Chicago-viite (17. p.)Não informado. Half-yearly Bulletin of Electric Energy Statistics for Europe. New York: United Nations, Economic Commission for Europe, 1956.
MLA-viite (8. p.)Não informado. Half-yearly Bulletin of Electric Energy Statistics for Europe. United Nations, Economic Commission for Europe, 1956.
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