CRESPO, Teresa. $C_4$-Extensions of $S_n$ as Galois Groups. Mathematica Scandinavica, Berkeley, CA, United States, v. 76, p. 214–220, 1995. DOI: 10.7146/math.scand.a-12537. Disponível em: https://journals.msp.org/mscand/article/view/1086. Acesso em: 25 jul. 2026.