ORLIK, P. Homotopy 4-Spheres Have Little Symmetry. MATHEMATICA SCANDINAVICA, [S. l.], v. 33, p. 275–278, 1973. DOI: 10.7146/math.scand.a-11490. Disponível em: https://www.mscand.dk/article/view/11490. Acesso em: 30 apr. 2024.