HAMLET, Oskar. Index Classes for Vector Fields and their Relation to Certain Characteristic Classes. Mathematica Scandinavica, Berkeley, CA, United States, v. 112, n. 2, p. 216–224, 2013. DOI: 10.7146/math.scand.a-15241. Disponível em: https://journals.msp.org/mscand/article/view/456. Acesso em: 24 jul. 2026.