Estimating a woman's risk of having a pregnancy associated with Down's syndrome using her age and serum alpha-fetoprotein level.Cuckle, Wald, Thompson1987 MayTijdschriftartikel
Physical activity, exercise, and physical fitness: definitions and distinctions for health-related researchCaspersen, K.E. Powell, Christenson1985 Mar-AprTijdschriftartikel
Epidemiology of community-acquired respiratory tract infections in adults. Incidence, etiology, and impact.Garibaldi1985 Jun 28Tijdschriftartikel
