TY - JOUR T1 - Abstracts JF - Thorax JO - Thorax SP - 190 LP - 204 DO - 10.1136/thx.7.2.190 VL - 7 IS - 2 A2 - , Y1 - 1952/06/01 UR - http://thorax.bmj.com/content/7/2/190.abstract N2 - 300 Multiple ChoicesThis is a pdf-only article and there is no markup to show you.full-text.pdf ER -