RT Journal Article SR Electronic T1 Alveolar partial pressures of carbon dioxide and oxygen measured by a helium washout technique. JF Thorax JO Thorax FD BMJ Publishing Group Ltd and British Thoracic Society SP 151 OP 151 DO 10.1136/thx.46.2.151 VO 46 IS 2 A1 E A Harris YR 1991 UL http://thorax.bmj.com/content/46/2/151.1.abstract AB