1. NBER Working Paper 14354;Aizer,2008
2. American School Counselor Association (ASCA) 2003 www.schoolcounselor.org/files/Natl%20Model%20Exec%20Summary_final.pdf
3. American School Counselor Association (ASCA) 2005 http://www.schoolcounselor.org/content.asp?pl=325&sl=133&contentid=535
4. American School Counselor Association (ASCA) 2006 http://www.schoolcounselor.org/content.asp?pl=325&sl=133&contentid=242