Keefer, L. E. (1966). Urban travel patterns for airports, shopping centers, and industrial plants. Highway Research Board, Division of Engineering, National Research Council, National Academy of Sciences.
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)Keefer, Louis E. Urban Travel Patterns for Airports, Shopping Centers, and Industrial Plants. Washington, D.C: Highway Research Board, Division of Engineering, National Research Council, National Academy of Sciences, 1966.
توثيق جمعية اللغة المعاصرة MLA (الإصدار التاسع)Keefer, Louis E. Urban Travel Patterns for Airports, Shopping Centers, and Industrial Plants. Highway Research Board, Division of Engineering, National Research Council, National Academy of Sciences, 1966.
تحذير: قد لا تكون هذه الاستشهادات دائما دقيقة بنسبة 100%.