CHUDZIAK, M. On a generalization of the Popoviciu equation on groups. Annales Universitatis Paedagogicae Cracoviensis Studia Mathematica, [S. l.], v. 9, p. 49–54, 2010. Disponível em: https://studmath.uken.krakow.pl/article/view/13245. Acesso em: 31 oct. 2026.