WRÓBEL, M. Lichawski-Matkowski-Miś theorem on locally defined operators for functions of several variables. Annales Universitatis Paedagogicae Cracoviensis Studia Mathematica, [S. l.], v. 7, p. 15–22, 2008. Disponível em: https://studmath.uken.krakow.pl/article/view/13265. Acesso em: 31 oct. 2026.