RT Journal Article SR Electronic T1 Systematic review of the efficacy of nasal CPAP JF Thorax JO Thorax FD BMJ Publishing Group Ltd and British Thoracic Society SP 414 OP 415 DO 10.1136/thx.53.5.414 VO 53 IS 5 A1 Douglas, Neil J YR 1998 UL http://thorax.bmj.com/content/53/5/414.abstract AB