Epstein, M., Atkins, M., Cullinan, D., Kutash, K., & Weaver, R. (2008). Reducing behavior problems in the elementary school classroom: A practice guide (NCEE 2008-012). Washington, DC: National Center for Education Evaluation and Regional Assistance, Institute of Education Sciences, U.S. Department of Education. Retrieved from http://ies.ed.gov/ncee/wWc/PracticeGuide.aspx?sid=4
Gallup Inc. (2013). U.S. overall Gallup student poll results. Retrieved from http://www.gallupstudentpoll.com/174020/2013-gallup-student-poll-overall-report.aspx
Gallup Inc. (2014). U.S. overall Gallup student poll results. Retrieved from http://www.gallup.com/services/180029/gallup-student-poll-2014-overall-report.aspx
Wentzel, K. R. (1993). Does being good make the grade? Social behavior and academic competence in middle school. Journal of Educational Psychology, 85 (2), 357-364.