Clinical epidemiology :
Fletcher, Robert H.
Clinical epidemiology : the essentials / Robert H. Fletcher, Suzanne W. Fletcher, Edward H. Wagner. - 2nd ed. - Baltimore : Williams & Wilkins, c1988. - xiii, 246 p. : ill. ; 23 cm.
Clinical epidemiology : the essentials / Robert H. Fletcher, Suzanne W. Fletcher, Edward H. Wagner. - 2nd ed. - Baltimore : Williams & Wilkins, c1988. - xiii, 246 p. : ill. ; 23 cm.