TY - JOUR T1 - AUTHORS' REPLY JF - Thorax JO - Thorax SP - 688 LP - 688 DO - 10.1136/thx.46.9.688-a VL - 46 IS - 9 AU - Jon Goldman AU - Martin Muers Y1 - 1991/09/01 UR - http://thorax.bmj.com/content/46/9/688.2.abstract N2 - 300 Multiple ChoicesThis is a pdf-only article and there is no markup to show you.full-text.pdf ER -