GONCALVES, D. L. Generalized classes of groups, $C$-nilpotent spaces and "The Hurewicz theorem". MATHEMATICA SCANDINAVICA, [S. l.], v. 53, p. 39–61, 1983. DOI: 10.7146/math.scand.a-12015. Disponível em: https://www.mscand.dk/article/view/12015. Acesso em: 24 nov. 2024.