RT Journal Article SR Electronic T1 Prescription opioid use in advanced COPD: benefits, perils and controversies JF European Respiratory Journal JO Eur Respir J FD European Respiratory Society SP 1700479 DO 10.1183/13993003.00479-2017 VO 49 IS 6 A1 Nicholas T. Vozoris YR 2017 UL http://erj.ersjournals.com/content/49/6/1700479.abstract AB