1. Has the prevalence of asthma increased in children?;Burney,1990
2. Trends in the hospitalisation for acute childhood asthma, 1970–84;Halfon;Am J Public Health,1986
3. Is the prevalence of asthma changing?;Anderson;Arch Dis Child,1989
4. Why has the utilization of antiasthmatics increased in Finland?;Klaukka;J Clin Epidemiol,1991
5. Epidemiology;Sears,1992