Não informado. Transportation: Current literature. U.S. Department of Transportation.
Chicago-referens (17:e uppl.)Não informado. Transportation: Current Literature. Washington: U.S. Department of Transportation.
MLA-referens (8:e uppl.)Não informado. Transportation: Current Literature. U.S. Department of Transportation.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.