RT Journal Article SR Electronic T1 Genetic and environment in asthma: the answer of twin studies JF European Respiratory Journal JO Eur Respir J FD European Respiratory Society SP 2 OP 4 DO 10.1183/09031936.99.13100299 VO 13 IS 1 A1 Koppelman, GH A1 Los, H A1 Postma, DS YR 1999 UL http://erj.ersjournals.com/content/13/1/2.abstract AB