Authors: C C Butler; M J Kelly; K Hood; T Schaberg; H Melbye; M Serra-Prat; F Blasi; P Little; T Verheij; S Mölstad; M Godycki-Cwirko; P Edwards; J Almirall; A Torres; U-M Rautakorpi; J Nuttall; H Goossens; S Coenen Journal: Eur Respir J Date: 2011-03-15 Impact factor: 16.671