Não informado. (1956). Half-yearly Bulletin of Electric Energy Statistics for Europe. United Nations, Economic Commission for Europe.
Παραπομπή σε μορφή Chicago (17η εκδ.)Não informado. Half-yearly Bulletin of Electric Energy Statistics for Europe. New York: United Nations, Economic Commission for Europe, 1956.
Παραπομπή σε μορφή MLA (8th εκδ.)Não informado. Half-yearly Bulletin of Electric Energy Statistics for Europe. United Nations, Economic Commission for Europe, 1956.
Πρόσοχή: Οι παραπομπές μπορεί να μην είναι 100% ακριβείς.