JOHNSEN, V. Hva er en vinkel?. NOMAD Nordic Studies in Mathematics Education, [S. l.], v. 4, n. 1, p. 25–49, 1996. DOI: 10.7146/nomad.v4i1.146193. Disponível em: https://tidsskrift.dk/NOMAD/article/view/146193. Acesso em: 9 jan. 2025.