LINDSTRÖM, Bernt. On Group and Nongroup Perfect Codes in $q$ Symbols. Mathematica Scandinavica, Berkeley, CA, United States, v. 25, p. 149–158, 1969. DOI: 10.7146/math.scand.a-10952. Disponível em: https://journals.msp.org/mscand/article/view/2392. Acesso em: 25 jul. 2026.