Contributions of observational evidence to prevention research.
Hennekens
C H
CH
Harvard Medical School, Division of Preventive Medicine, Brigham and Women's Hospital, Boston, Massachusetts 02215.
Buring
J E
JE
D004812:Epidemiologic Methods; D006801:Humans; D011315:Preventive Medicine; D012106:Research; D012306:Risk; D012307:Risk Factors