PYM, John S. On Almost Periodic Compactifications. Mathematica Scandinavica, Berkeley, CA, United States, v. 12, p. 189–198, 1963. DOI: 10.7146/math.scand.a-10682. Disponível em: https://journals.msp.org/mscand/article/view/2642. Acesso em: 25 jul. 2026.