1. Cognitive tutors: lessons learned;Anderson;The Journal of the Learning Sciences,1995
2. Prosody-based automatic detection of annoyance and frustration;Ang,2002
3. Affect in Language Learning;Arnold,1999
4. Baker, R.S., 2005. Designing intelligent tutors that adapt to when students game the system. Doctoral Dissertation. CMU Technical Report CMU-HCII-05-104.
5. Modeling and understanding students’ off-task behavior in intelligent tutoring systems;Baker,2007