BOOTH, Peter I. Cancellation and non-cancellation amongst products of spherical fibrations. Mathematica Scandinavica, Berkeley, CA, United States, v. 66, p. 33–43, 1990. DOI: 10.7146/math.scand.a-12290. Disponível em: https://journals.msp.org/mscand/article/view/1334. Acesso em: 24 jul. 2026.