求助两篇英文文献,谢谢大家!
第一篇:
作者:Heckman, J. and R. Robb
题目:Alternative methods for evaluating the impact of interventions
来源: in: J. Heckman and B. Singer, eds., Longitudinal analysis of labor market data (Cambridge University Press for Econometric Society Monograph Series, New York, NY) 156-246.
第二篇:作者:Heckman, J. and R. Robb
题目:Alternative methods for evaluating the impact of interventions: an overview
来源:Journal of Econometrics, 1985, 30(1-2):239-267.
[此贴子已经被作者于2008-12-29 0:18:09编辑过]