Pegrum, D. F. (1968). transportation economics and public policy. Illinois.
Cita Chicago (17th ed.)Pegrum, Dudley F. Transportation Economics and Public Policy. Homewood: Illinois, 1968.
Cita MLA (9th ed.)Pegrum, Dudley F. Transportation Economics and Public Policy. Illinois, 1968.
Atenció: Aquestes cites poden no estar 100% correctes.