National Research Council (U.S.). Transportation Research Board & National Research Council (U.S.). Transportation Research Board. Meeting. (2001). Traffic control devices, visibility, and rail-highway grade crossings, 2001. National Academy Press.
Cita Chicago (17th ed.)National Research Council (U.S.). Transportation Research Board i National Research Council (U.S.). Transportation Research Board. Meeting. Traffic Control Devices, Visibility, and Rail-highway Grade Crossings, 2001. Washington, D.C: National Academy Press, 2001.
Cita MLA (9th ed.)National Research Council (U.S.). Transportation Research Board i National Research Council (U.S.). Transportation Research Board. Meeting. Traffic Control Devices, Visibility, and Rail-highway Grade Crossings, 2001. National Academy Press, 2001.