Não informado. (1949). Annual Bulletin of Transport Statistics for Europe. United Nations, Economic Commission for Europe.
Chicago-viite (17. p.)Não informado. Annual Bulletin of Transport Statistics for Europe. Geneve, Suíça: United Nations, Economic Commission for Europe, 1949.
MLA-viite (8. p.)Não informado. Annual Bulletin of Transport Statistics for Europe. United Nations, Economic Commission for Europe, 1949.
Varoitus: Nämä viitteet eivät aina ole täysin luotettavia.