1. ATX. Algoritmo de Colocação de professores (in Portuguese). ATX Software press release (November 2004)
2. Back, R.-J., Mannila, L., Peltomaki, M., Sibelius, P.: Structured derivations: A logic based approach to teaching mathematics. In: FORMED 2008: Formal Methods in Computer Science Education, Budapest (2008)
3. Back, R.-J., von Wright, J.: Mathematics with a little bit of logic: Structured derivations in high-school mathematics
4. Back, R.-J., von Wright, J.: Doing high school mathematics carefully. Technical report (1997)
5. Backhouse, R.C.: Mathematics and programming. A revolution in the art of effective reasoning. Inaugural Lecture, School of Computer Science and IT, University of Nottingham (2001)