1. Wahn U, Lau S, Bergmann R et al. Indoor allergen exposure is a risk factor for sensitisation during the first three years of life. J Allergy Clin Immunol 1997; 99: 763–769. 2. Platts-Mills TAE, et al. Indoor allergens and asthma: Report of the Third International Workshop. J Allergy Clin Immunol 1997; 100: S1–S24. 3. van der Heide S, et al. Seasonal differences in airway hyperresponsiveness ...