JOHANSSON, B.; EMANUELSSON, G. Ett nytt dubbelnummer. NOMAD Nordic Studies in Mathematics Education, [S. l.], v. 4, n. 2-3, p. 4–6, 1996. DOI: 10.7146/nomad.v4i2-3.146226. Disponível em: https://tidsskrift.dk/NOMAD/article/view/146226. Acesso em: 9 jan. 2025.