National Cooperative Highway Research Program, National Research Council (U.S.). Transportation Research Board, & Potts, I. B. (2004). Safety of U-turns at unsignalized median openings. Transportation Research Board.
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)National Cooperative Highway Research Program, National Research Council (U.S.). Transportation Research Board, و Ingrid B. Potts. Safety of U-turns at Unsignalized Median Openings. Washington, D.C: Transportation Research Board, 2004.
توثيق جمعية اللغة المعاصرة MLA (الإصدار التاسع)National Cooperative Highway Research Program, et al. Safety of U-turns at Unsignalized Median Openings. Transportation Research Board, 2004.
تحذير: قد لا تكون هذه الاستشهادات دائما دقيقة بنسبة 100%.