Clinical epidemiology : the essentials / Robert H. Fletcher, Suzanne W. Fletcher. Fletcher, Robert H. Fletcher, Suzanne W. Clinical epidemiology. Epidemiologic Methods. RA652.2.C55 F57 2005 614.4 22 FLC Includes bibliographical references and index. Philadelphia : Lippincott Williams & Wilkins, c2005. c2005. 2005 Text xv, 252 p. : http://www.loc.gov/catdir/toc/ecip055/2004029660.html http://www.loc.gov/catdir/enhancements/fy0712/2004029660-d.html eng