PT  - JOURNAL ARTICLE
AU  - Suissa, S
AU  - Ernst, P
TI  - Biases in the observational study of β blockers in COPD
DP  - 2008 Nov 01
TA  - Thorax
PG  - 1026--1027
VI  - 63
IP  - 11
4099  - http://thorax.bmj.com/content/63/11/1026.3.short
4100  - http://thorax.bmj.com/content/63/11/1026.3.full
SO  - Thorax2008 Nov 01; 63