RT Journal Article SR Electronic T1 Targeted oxygen therapy in the prehospital management of patients with chronic obstructive pulmonary disease JF Thorax JO Thorax FD BMJ Publishing Group Ltd and British Thoracic Society SP 781 OP 781 DO 10.1136/thx.2011.159434 VO 66 IS 9 A1 William M Ricketts YR 2011 UL http://thorax.bmj.com/content/66/9/781.abstract AB