(1968). Highway Research Abstracts. Washington: National Research Council, Transportation Research Board, Highway Research Information Service.
Παραπομπή Chicago StyleHighway Research Abstracts. Washington: National Research Council, Transportation Research Board, Highway Research Information Service, 1968.
Παραπομπή MLAHighway Research Abstracts. Washington: National Research Council, Transportation Research Board, Highway Research Information Service, 1968.
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