Cooper, D. Y., III, & Ledger, M. A. (1990). Innovation and tradition at the University of Pennsylvania School of Medicine: An anecdotal journey. University of Pennsylvania Press.
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)Cooper, David Y., III, و Marshall A. Ledger. Innovation and Tradition at the University of Pennsylvania School of Medicine: An Anecdotal Journey. Philadelphia: University of Pennsylvania Press, 1990.
توثيق جمعية اللغة المعاصرة MLA (الإصدار التاسع)Cooper, David Y., III, و Marshall A. Ledger. Innovation and Tradition at the University of Pennsylvania School of Medicine: An Anecdotal Journey. University of Pennsylvania Press, 1990.
تحذير: قد لا تكون هذه الاستشهادات دائما دقيقة بنسبة 100%.