1. Author, 2015
2. Author, 2019
3. Author et al., 2019
4. Alibert, D. and Thomas, M. (1991). Research on mathematical proof. In D. Tall (Ed.) Advanced Mathematical Thinking (pp. 215-230). Kluwer: The Netherlands.
5. Balacheff, N. (1988). Aspects of proof in pupils' practice of school mathematics. In D. Pimm (ed.), Mathematics, teachers and children (pp. 216-235). London: Hodder & Stoughton.