- Saarland University, Saarbrücken, Germany, (2007)
- Department of Mathematics, Stockholm University, (2006)
- Artificial Intelligence in Education -- Building Learning Systems tat Care: From Knowledge Representation to Affective Modelling, 200, page 599--601. Amsterdam, IOS Press, (2009)
- KI 2009: Advances in Artificial Intelligence, 5803, page 289-279. Berlin Heidelberg, Springer Verlag, (2009)
- Proceedings of The 12th International Conference on Artificial Intelligence in Education, page 443 -- 450. Amsterdam, IOS Press, (2005)


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