HANSEN, H. C. On Cycles in Flag Manifolds. Mathematica Scandinavica, Berkeley, CA, United States, v. 33, p. 269–274, 1973. DOI: 10.7146/math.scand.a-11489. Disponível em: https://journals.msp.org/mscand/article/view/2178. Acesso em: 25 jul. 2026.