PT - JOURNAL ARTICLE AU - Hetzel, M R TI - AUTHOR'S REPLY AID - 10.1136/thx.46.11.861-a DP - 1991 Nov 01 TA - Thorax PG - 861--861 VI - 46 IP - 11 4099 - http://thorax.bmj.com/content/46/11/861.2.short 4100 - http://thorax.bmj.com/content/46/11/861.2.full SO - Thorax1991 Nov 01; 46