00861nam a2200241 a 4500 1/342 210201s1998 enk b 1 0 fre d 0192627449 352 GR-PeUP 614.4΄028 EL Elwood, Mark J. Critical appraisal of epidemiological studies and clinical trials / J. Mark Elwood 2nd ed. New york : Oxford University Press, 1998 448 p. : diagr. ; 24 cm. Includes bibliographical references & index Epidemiology Research Methodology. Clinical trials. Epidemiology Research Evaluation. Diseases Causes and theories of causation. INST UNIPILB MAIN 20040709 614.4΄028 EL 00135744 00135744 LOAN 0 1 /webopac/covers/02/352_0192627449.jpg