HEGENBARTH, Friedrich. On a certain formula for exotic characteristic classes I. Mathematica Scandinavica, Berkeley, CA, United States, v. 44, p. 73–91, 1979. DOI: 10.7146/math.scand.a-11796. Disponível em: https://journals.msp.org/mscand/article/view/1854. Acesso em: 25 jul. 2026.