Pratt, R. H. (1991). Collection and application of ridership data on rapid transit systems. Transportation Research Board, National Research Council.
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)Pratt, Richard H. Collection and Application of Ridership Data on Rapid Transit Systems. Washington, D.C: Transportation Research Board, National Research Council, 1991.
توثيق جمعية اللغة المعاصرة MLA (الإصدار التاسع)Pratt, Richard H. Collection and Application of Ridership Data on Rapid Transit Systems. Transportation Research Board, National Research Council, 1991.
تحذير: قد لا تكون هذه الاستشهادات دائما دقيقة بنسبة 100%.