RT Journal Article SR Electronic T1 A New Index of the Intrapulmonary Mixture of Inspired Air JF Thorax JO Thorax FD BMJ Publishing Group Ltd and British Thoracic Society SP 111 OP 116 DO 10.1136/thx.7.1.111 VO 7 IS 1 A1 Margaret R. Becklake YR 1952 UL http://thorax.bmj.com/content/7/1/111.abstract AB