National Research Council (U.S.). Transportation Research Board. (1993). Nonmotorized transportation research and issues: Operations and safety; planning and administration. National Academy Press.
Dyfyniad Arddull ChicagoNational Research Council (U.S.). Transportation Research Board. Nonmotorized Transportation Research and Issues: Operations and Safety; Planning and Administration. Washington, D.C: National Academy Press, 1993.
Dyfyniad MLANational Research Council (U.S.). Transportation Research Board. Nonmotorized Transportation Research and Issues: Operations and Safety; Planning and Administration. National Academy Press, 1993.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.