National Cooperative Highway Research Program, Kriger, D. S., Shiu, S., & Naylor, S. (2006). Estimating toll road demand and revenue. Transportation Research Board, National Research Council.
Dyfyniad Arddull ChicagoNational Cooperative Highway Research Program, David S. Kriger, Suzette Shiu, and Sasha Naylor. Estimating Toll Road Demand and Revenue. Washington, D.C: Transportation Research Board, National Research Council, 2006.
Dyfyniad MLANational Cooperative Highway Research Program, et al. Estimating Toll Road Demand and Revenue. Transportation Research Board, National Research Council, 2006.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.