HEGENBARTH, F. On a certain formula for exotic characteristic classes I. MATHEMATICA SCANDINAVICA, [S. l.], v. 44, p. 73–91, 1979. DOI: 10.7146/math.scand.a-11796. Disponível em: https://www.mscand.dk/article/view/11796. Acesso em: 5 may. 2024.