TY  - JOUR
A1  - Rassen, J.A.
A1  - Brookhart, M.A.
A1  - Glynn, R.J.
A1  - Mittleman, M.A.
A1  - Schneeweiss, S.
T1  - Instrumental variables I: Instrumental variables exploit natural variation in nonexperimental data to estimate causal relationships
Y1  - 2009
DO  - 10.1016/j.jclinepi.2008.12.005
JF  - Journal of Clinical Epidemiology
VL  - 62
IS  - 12

ER  -