FOLNER, Erling. Besicovitch almost periodic functions in arbitrary groups. Mathematica Scandinavica, Berkeley, CA, United States, v. 5, p. 47–53, 1957. DOI: 10.7146/math.scand.a-10488. Disponível em: https://journals.msp.org/mscand/article/view/2835. Acesso em: 8 sep. 2026.