APA-ийн эшлэл(7 дахь хэвлэлт)

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.

Чикаго-гийн эшлэл (17 дахь хэвлэлт)

Cooper, David Y., III, ба Marshall A. Ledger. Innovation and Tradition at the University of Pennsylvania School of Medicine: An Anecdotal Journey. Philadelphia: University of Pennsylvania Press, 1990.

MLA -ийн эшлэл (9 дэх хэвлэлт)

Cooper, David Y., III, ба Marshall A. Ledger. Innovation and Tradition at the University of Pennsylvania School of Medicine: An Anecdotal Journey. University of Pennsylvania Press, 1990.