KRISTENSEN, Leif; PEDERSEN, Erik K. The $\mathcal{A}$-Module Structure for the Cohomology of Two-Stage Spaces. Mathematica Scandinavica, Berkeley, CA, United States, v. 30, p. 95–106, 1972. DOI: 10.7146/math.scand.a-11067. Disponível em: https://journals.msp.org/mscand/article/view/2263. Acesso em: 25 jul. 2026.