SZULKIN, Andrzej. Local structure of the zero-sets of differentiable mappings and application to bifurcation theory. Mathematica Scandinavica, Berkeley, CA, United States, v. 45, p. 232–242, 1979. DOI: 10.7146/math.scand.a-11838. Disponível em: https://journals.msp.org/mscand/article/view/1811. Acesso em: 25 jul. 2026.