Helliar-Symons, R. D., & Lynam, D. A. (1989). Accident reduction and prevention programmes in highway authorities- 1987. Crowthorne: Transport and Road Research Laboratory.
Παραπομπή Chicago StyleHelliar-Symons, R. D., and D. A. Lynam. Accident Reduction and Prevention Programmes in Highway Authorities- 1987. Crowthorne: Transport and Road Research Laboratory, 1989.
Παραπομπή MLAHelliar-Symons, R. D., and D. A. Lynam. Accident Reduction and Prevention Programmes in Highway Authorities- 1987. Crowthorne: Transport and Road Research Laboratory, 1989.
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