KOVAL, R. F. Classification of Quadratic Parastrophically Uncancelable Functional Equations for Five Object Variables on Quasigroups. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 57, n. 8, p. 1058 – 1068, 2005. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/3664. Acesso em: 5 dec. 2025.