RT Journal Article SR Electronic T1 Terminology, Definitions, and Classification of Chronic Pulmonary Emphysema and Related Conditions JF Thorax JO Thorax FD BMJ Publishing Group Ltd and British Thoracic Society SP 286 OP 299 DO 10.1136/thx.14.4.286 VO 14 IS 4 YR 1959 UL http://thorax.bmj.com/content/14/4/286.abstract AB