Anderson T. W., 1976, Journal of the Royal Statistical Society, Ser. B, 38, 1
10.1002/(SICI)1099-1255(199901/02)14:1<57::AID-JAE501>3.0.CO;2-G
10.1002/(SICI)1099-1255(199901/02)14:1<69::AID-JAE521>3.0.CO;2-7
10.1016/0304-4076(92)90032-M
10.1017/S0266466600007519
10.1016/0304-405X(94)90029-9
10.1016/S0304-3932(99)00023-9
Imbens G. W., 2002, Journal of Business & Economic Statistics, forthcoming.
10.1016/0304-4076(94)01643-E
10.1016/0304-3932(90)90024-X
10.1016/S0165-1765(02)00083-6
10.1198/07350010152596646
10.1162/rest.1997.79.2.348
10.1016/S0304-4076(99)00006-8
10.1111/j.0013-0133.1997.174.x