1. Aczel, J.C., Fung, P., Bornat, R.: Using Computers to Learn Logic: Undergraduates’ Experiences. In: Advanced Research in Computers and Communications in Education, vol. 1(55), pp. 875–882 (1999)
2. Anderson, J.R., Corbett, A.T., Koedinger, K.R., Pelletier, R.: Cognitive Tutors: Lessons Learned. The Journal of the Learning Sciences 4(2), 167–207 (1995)
3. Barwise, J., Etchemendy, J.: The Language of First-Order Logic. Cambridge University Press, Cambridge (1992)
4. Beal, C.R., Qu, L., Lee, H.: Mathematics Motivation and Achievement as Predictors of High School Students’ Guessing and Help-Seeking with Instructional Software. J. Comput. Assisted Learn. 24, 507–514 (2008)
5. Beal, C.R., Walles, R., Arroyo, I., et al.: On-Line Tutoring for Math Achievement Testing: A Controlled Evaluation. Journal of Interactive Online Learning 26, 43–55 (2007)