Siblings, multiple births, and the incidence of allergic disease: a birth cohort study using the West Midlands general practice research database

McKeever TM, Lewis SA, Smith C, Collins J, Heatlie H, Frischer M, Hubbard R. Siblings, multiple births, and the incidence of allergic disease: a birth cohort study using the West Midlands general practice research database. Thorax. 2001; 56(10): 758-62.