Board, N. R. C. T. R. (1991). Geometric design considerations 1991. Washington, D.C : Transportation Research Board, National Research Council.
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)Board, National Research Council. Transportation Research. Geometric Design Considerations 1991. Washington, D.C : Transportation Research Board, National Research Council, 1991.
توثيق جمعية اللغة المعاصرة MLA (الإصدار التاسع)Board, National Research Council. Transportation Research. Geometric Design Considerations 1991. Washington, D.C : Transportation Research Board, National Research Council, 1991.
تحذير: قد لا تكون هذه الاستشهادات دائما دقيقة بنسبة 100%.