MENNICKE, J. A Remark on the Congruence Subgroup Problem. MATHEMATICA SCANDINAVICA, [S. l.], v. 86, n. 2, p. 206–222, 2000. DOI: 10.7146/math.scand.a-14289. Disponível em: https://www.mscand.dk/article/view/14289. Acesso em: 23 nov. 2024.