1. Using the longitudinal structure of earnings to estimate the effects of training programs;Ashenfelter;Rev. Econ. Stat.,1985
2. Economic Potential of Biological Substitutes for Agrochemicals;Birthal,2003
3. How regression artifacts in quasi-experimental evaluations can mistakenly make compensatory education look harmful;Campbell,1970
4. Experimental and Quasi-experimental Designs for Research;Campbell,1966
5. Quasi-experimentation: Design and Analysis Issues for Field Settings;Cook,1979