1. Abel, A., Chang, B., Pfenning, F.: Human-readable machine-verifiable proofs for teaching constructive logic. In: Egly, U., Fiedler, A., Horacek, H., and Schmitt, S. (eds.) Proceedings of the Workshop on Proof Transformations, Proof Presentations and Complexity of Proofs (PTP01) (2001)
2. Andrews, P.B., Brown, C.E., Pfenning, F., Bishop, M., Issar, S., Xi, H.: ETPS: a system to help students write formal proofs. J. Autom. Reason. 32, 75–92 (2004)
3. Arefi, F., Hughes, C.E., Workman, D.A.: Automatically generating visual syntax-directed editors. Commun. ACM 33(3), 349–360 (1990)
4. Aspinall, D., Lüth, C., Winterstein, D.: Parsing, editing, proving: the PGIP Display Protocol. In: International Workshop on User Interfaces for Theorem Provers 2005 (UITP’05) (2005)
5. Baker, R.S., Corbett, A.T., Koedinger, K.R., Wagner, A.: Off-task behavior in the cognitive tutor classroom: when students “game the system.” In: Dykstra-Erickson, E., Tscheligi, M. (eds.) Proceedings of ACM CHI 2004 Conference on Human Factors in Computing Systems, pp. 383–390 (2004)