RT Journal Article SR Electronic T1 Oxygen therapy JF Clinical Medicine JO Clin Med FD Royal College of Physicians SP 156 OP 159 DO 10.7861/clinmedicine.9-2-156 VO 9 IS 2 A1 Luke S Howard YR 2009 UL http://www.rcpjournals.org/content/9/2/156.abstract AB