KRISTENSEN, Leif; MADSEN, Ib. On Evaluation of Higher Order Cohomology Operations. MATHEMATICA SCANDINAVICA, [S. l.], v. 20, p. 114–130, 1967. DOI: 10.7146/math.scand.a-10826. Disponível em: https://www.mscand.dk/article/view/10826. Acesso em: 5 dec. 2025.