00540nas a2200193   4500000000100000000000100001008004100002100001600043700001300059700001300072700001500085700001500100700001600115700001500131245015000146300001100296490000700307022003200314       2001                            d1 aT. McKeever1 aS. Lewis1 aC. Smith1 aJ. Collins1 aH. Heatlie1 aM. Frischer1 aR. Hubbard00aSiblings, multiple births, and the incidence of allergic disease: a birth cohort study using the West Midlands general practice research database  a758-620 v56  a0040-6376 (Print) 0040-6376