Pegrum, D. F. (1968). Transportation: Economics and public policy (Rev. ed.). R. D. Irwin.
Cita Chicago (17th ed.)Pegrum, Dudley Frank. Transportation: Economics and Public Policy. Rev. ed. Homewood, Ill.: R. D. Irwin, 1968.
Cita MLA (8th ed.)Pegrum, Dudley Frank. Transportation: Economics and Public Policy. Rev. ed. R. D. Irwin, 1968.
Atenció: Aquestes cites poden no estar 100% correctes.