WEIER, J. Invariante Schnittsysteme stetiger Transformationen. MATHEMATICA SCANDINAVICA, [S. l.], v. 7, p. 33–48, 1959. DOI: 10.7146/math.scand.a-10559. Disponível em: https://www.mscand.dk/article/view/10559. Acesso em: 3 may. 2024.