BAAS, Nils Andreas. On Bordism Theory of Manifolds with Singularities. Mathematica Scandinavica, Berkeley, CA, United States, v. 33, p. 279–302, 1973. DOI: 10.7146/math.scand.a-11491. Disponível em: https://journals.msp.org/mscand/article/view/2173. Acesso em: 25 jul. 2026.