1. Respiratory Muscle Laboratory; Royal Brompton and Harefield N.H.S Trust, Royal Brompton Hospital; London UK
2. Department of Respiratory Medicine; Gartnavel General Hospital; Glasgow UK
3. Department of Cardiology, Guy's, King's and St. Thomas' School of Medicine; Kings College Hospital; London UK
4. Department of Respiratory Medicine, Guy's, King's and St. Thomas' School of Medicine; Kings College Hospital; London UK