BRATTSTRÖM, G. On $p$-groups as Galois groups. MATHEMATICA SCANDINAVICA, [S. l.], v. 65, p. 165–174, 1989. DOI: 10.7146/math.scand.a-12276. Disponível em: https://www.mscand.dk/article/view/12276. Acesso em: 14 apr. 2025.