RT Journal Article SR Electronic T1 Past, present and future JF Breathe JO Breathe FD European Respiratory Society SP 118 OP 119 DO 10.1183/18106838.0302.118 VO 3 IS 2 A1 A.K. Simonds YR 2006 UL http://breathe.ersjournals.com/content/3/2/118.abstract AB