FOLNER, E. Some special $W$-almost periodic sets on the integers. MATHEMATICA SCANDINAVICA, [S. l.], v. 53, p. 185–192, 1983. DOI: 10.7146/math.scand.a-12025. Disponível em: https://www.mscand.dk/article/view/12025. Acesso em: 30 apr. 2024.