FOLNER, Erling. Generalization of a theorem of Bogolioùboff to topological groups. With an appendix on Banach mean values in nonabelian groups. Mathematica Scandinavica, Berkeley, CA, United States, v. 2, p. 5–18, 1954. DOI: 10.7146/math.scand.a-10389. Disponível em: https://journals.msp.org/mscand/article/view/2928. Acesso em: 25 jul. 2026.