Não informado. (1949). Annual Bulletin of Transport Statistics for Europe. United Nations, Economic Commission for Europe.
Lua i Stíl Chicago (17ú heag.)Não informado. Annual Bulletin of Transport Statistics for Europe. Geneve, Suíça: United Nations, Economic Commission for Europe, 1949.
Lua MLA (8ú heag.)Não informado. Annual Bulletin of Transport Statistics for Europe. United Nations, Economic Commission for Europe, 1949.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.