(1967). Highway design and operational practices related to highway safety. Washington, D.C: [s.n.].
Παραπομπή Chicago StyleHighway Design and Operational Practices Related to Highway Safety. Washington, D.C: [s.n.], 1967.
Παραπομπή MLAHighway Design and Operational Practices Related to Highway Safety. Washington, D.C: [s.n.], 1967.
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