BREKKE, G.; GJONE, G. Developments and challenges. NOMAD Nordic Studies in Mathematics Education, [S. l.], v. 5, n. 3, p. 4–5, 1997. DOI: 10.7146/nomad.v5i3.146500. Disponível em: https://tidsskrift.dk/NOMAD/article/view/146500. Acesso em: 9 jan. 2025.