TY - JOUR T1 - Proceedings of the Thoracic Society JF - Thorax JO - Thorax SP - 288 LP - 290 DO - 10.1136/thx.18.3.288 VL - 18 IS - 3 A2 - , Y1 - 1963/09/01 UR - http://thorax.bmj.com/content/18/3/288.abstract N2 - 300 Multiple ChoicesThis is a pdf-only article and there is no markup to show you.full-text.pdf ER -