Davidson's principles and practice of medicine.   Principles and practice of medicine    - 21st ed. /  the editors, Nicki R. Colledge, Brian R. Walker, Stuart H. Ralston ; illustrated by Robert Britton.   - Edinburgh :  Churchill Livingstone Elsevier,  2010.   - xvi, 1360 p. :  ill. (chiefly col.), col. maps ;  27 cm.