PAPASTAVRIDIS, S. Imbeddings, immersions and integrability of characteristic classes,. MATHEMATICA SCANDINAVICA, [S. l.], v. 43, p. 177–184, 1978. DOI: 10.7146/math.scand.a-11773. Disponível em: https://www.mscand.dk/article/view/11773. Acesso em: 29 apr. 2024.