Urrutia I, Aguirre U, Sunyer J, Plana E, Muniozguren N, Martinez-Moratalla J. Changes in the prevalence of asthma in the Spanish cohort of the European Community Respiratory Health Survey (ECRHS-II). Arch. Bronconeumol. 2007 Aug;43(8):425-30.
Pueschel SM, Rothman KJ, Ogilby JD. Birth weight of children with down's syndrome. Am J Ment Defic. 1976 Jan;80(4):442-5.