TY  - JOUR
TI  - On the Role of the Propensity Score in Efficient Semiparametric Estimation of Average Treatment Effects
AU  - Jinyong Hahn
JO  - Econometrica
PY  - 1998
VL  - 66
IS  - 2
DO  - 10.2307/2998560
UR  - https://doi.org/10.2307/2998560
ER  -