Pegrum, D. F. (1963). Transportation: Economics and public policy. Irwin.
Dyfyniad Arddull ChicagoPegrum, Dudley Frank. Transportation: Economics and Public Policy. Homewood, Ill: Irwin, 1963.
Dyfyniad MLAPegrum, Dudley Frank. Transportation: Economics and Public Policy. Irwin, 1963.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.