HAMLET, Oskar. Index Classes for Vector Fields and their Relation to Certain Characteristic Classes. MATHEMATICA SCANDINAVICA, [S. l.], v. 112, n. 2, p. 216–224, 2013. DOI: 10.7146/math.scand.a-15241. Disponível em: https://tidsskrift.dk/math/article/view/15241. Acesso em: 14 aug. 2026.