1. Balfanz , R. Legters , N. 2004 Locating the dropout crisis http://www.csos.jhu.edu/crespar/techReports/Report70.pdf
2. Jerald , D. C. 2006 Identifying potential dropouts: Key lessons for building an early warning data system http://www.achieve.org/files/FINAL-dropouts_0.pdf
3. Jerald 2006