Não informado. Quarterly Bulletin of Coal Statistics for Europe. United Nations, Economic Commission for Europe, Coal Division.
Lua i Stíl Chicago (17ú heag.)Não informado. Quarterly Bulletin of Coal Statistics for Europe. Geneva, Suíça: United Nations, Economic Commission for Europe, Coal Division.
Lua MLA (8ú heag.)Não informado. Quarterly Bulletin of Coal Statistics for Europe. United Nations, Economic Commission for Europe, Coal Division.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.