Gibbons, J. W., Sellin, T., & Lambert, R. D. (1958). Highway safety and traffic control. The American Academy of Political and Social Science.
Cita Chicago (17th ed.)Gibbons, John W., Thorsten Sellin, i Richard D. Lambert. Highway Safety and Traffic Control. Philadelphia: The American Academy of Political and Social Science, 1958.
Cita MLA (9th ed.)Gibbons, John W., et al. Highway Safety and Traffic Control. The American Academy of Political and Social Science, 1958.
Atenció: Aquestes cites poden no estar 100% correctes.