1. Astin, A. W. (1993). What matters in college: Four critical years revisited. San Francisco: Jossey-Bass.
2. Astin, A. W., & Sax, L. J. (1998). How undergraduates are affected by service participation. The Journal of College Student Development, 39(3), 251–263.
3. Astin, A. W., Vogelgesang, L. J., Ikeda, E. K., & Yee, J. A. (2000). How service learning affects students. Los Angeles: Higher Education Research Institute University of California.
4. Benjamini, Y., & Hochberg, Y. (1995). Controlling the false discovery rate: A practical and powerful approach to multiple testing. Journal of the Royal Statistical Society, Series B, 57, 289–300.
5. Bjorner, J. B., Smith, K. J., Stone, C., & Sun, X. (2007). IRTFIT: A macro for item fit and local dependence tests under IRT models. USA: QualityMetric Incorporated School of Education, University of Pittsburgh.