Benzon, Honorio T 
Essentials of pain medicine /  editors, Honorio T. Benzon ... [et al.] ; associate editors, Robert W. Hurley ... [et al.].   - 3rd ed.   - Philadelphia, Pa. ;  London :  Elsevier/Saunders,  2011.   - xix, 664 p. :  ill. ;  29 cm.