National Research Council (U.S.). Highway Research Board. (1973). Freeway operational improvements. National Academy of Science - National Research Council.
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)National Research Council (U.S.). Highway Research Board. Freeway Operational Improvements. Washington, D.C: National Academy of Science - National Research Council, 1973.
توثيق جمعية اللغة المعاصرة MLA (الإصدار التاسع)National Research Council (U.S.). Highway Research Board. Freeway Operational Improvements. National Academy of Science - National Research Council, 1973.
تحذير: قد لا تكون هذه الاستشهادات دائما دقيقة بنسبة 100%.