1. Abadie, A., & Imbens, G. W. (2011). Bias-corrected matching estimators for average treatment effects. Journal of Business and Economic Statistics, 29(1), 1–11.
2. Adelman, C. (2006). The toolbox revisited: Paths to degree completion from high school through college. Washington, DC: U.S. Department of Education.
3. Alfonso, M. (2006). The impact of community college attendance on baccalaureate attainment. Research in Higher Education, 47(8), 873–903.
4. Astin, A. W. (1977). Four critical years: Effects of college on beliefs, attitudes, and knowledge. San Francisco, CA: Jossey-Bass.
5. Astin, A. W. (1993). What matters in college? Four critical years revisited. San Francisco, CA: Jossey-Bass.