1. Armstrong, E. A., & Hamilton, L. T. (2013). Paying for the party: How college maintains inequality. Cambridge, MA: Harvard University Press.
2. Arum, R., & Roksa, J. (2011). Academically adrift: Limited learning on college campuses. Chicago: University of Chicago Press.
3. Astin, A. W. (1984). Student involvement: A developmental theory for higher education. Journal of College Student Personnel, 25, 297–308.
4. Astin, A. W. (1993). What matters in college?: Four critical years revisited. San Francisco: Jossey-Bass.
5. Babcock, P., & Marks, M. (2011). The falling time cost of college: Evidence from half a century of time use data. Review of Economics and Statistics, 93, 468–478.