1. Brody School of Medicine; Section of Pulmonary & Critical Care Medicine; Room E-149B, Brody Medical Science Building 600 Moye Blvd Greenville North Carolina USA 27858
2. Duke University; Center for Clinical Health Policy Research; 2200 W. Main Street, Suite 220 Durham NC USA 27705
3. York District Hospital; Respiratory Medicine; Wigginton Rd York North Yorks UK YO31 8HE