KRISTENSEN, Leif; MADSEN, Ib. On Evaluation of Higher Order Cohomology Operations. Mathematica Scandinavica, Berkeley, CA, United States, v. 20, p. 114–130, 1967. DOI: 10.7146/math.scand.a-10826. Disponível em: https://journals.msp.org/mscand/article/view/2500. Acesso em: 25 jul. 2026.