RT Journal Article SR Electronic T1 Measurement of respiratory muscle strength. JF Thorax JO Thorax FD BMJ Publishing Group Ltd and British Thoracic Society SP 1131 OP 1135 DO 10.1136/thx.50.11.1131 VO 50 IS 11 A1 Polkey, M I A1 Green, M A1 Moxham, J YR 1995 UL http://thorax.bmj.com/content/50/11/1131.abstract AB