EHMKE, T.; PESONEN, M. E.; HAAPASALO, L. Assessment of university students’ understanding of abstract binary operations. NOMAD Nordic Studies in Mathematics Education, [S. l.], v. 15, n. 4, p. 25–40, 2010. DOI: 10.7146/nomad.v15i4.148287. Disponível em: https://tidsskrift.dk/NOMAD/article/view/148287. Acesso em: 8 jan. 2025.