Jeffery, D. J. (1981). Ways and means for improving driver route guidance. Transport and Road Research Laboratory.
Dyfyniad Arddull ChicagoJeffery, D. J. Ways and Means for Improving Driver Route Guidance. Crowthorne, Berkshire: Transport and Road Research Laboratory, 1981.
Dyfyniad MLAJeffery, D. J. Ways and Means for Improving Driver Route Guidance. Transport and Road Research Laboratory, 1981.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.