HAMIDOUNE, Y. O.; RÖDSETH, Ö. J. On Bases for $\sigma$-Finite Groups. MATHEMATICA SCANDINAVICA, [S. l.], v. 78, p. 246–254, 1996. DOI: 10.7146/math.scand.a-12586. Disponível em: https://www.mscand.dk/article/view/12586. Acesso em: 29 apr. 2024.