1. Semiparametric estimation of instrumental variable models for causal effects;Abadie,2000
2. Abstract of Form 5500 Annual Reports, 1993–1999,1993
3. How workers use 401(k) plans: The participation, contribution, and withdrawal decisions;Bassett;National Tax Journal,1998
4. Beller, D., 2000. Office of Policy and Research, Pension and Welfare Benefits Administration, United States Department of Labor. Personal communication.
5. The effectiveness of adjustment by subclassification in removing bias in observational studies;Cochran;Biometrics,1968