FOLNER, Erling. Generalization of the general Diophantine approximation theorem of Kronecker. Mathematica Scandinavica, Berkeley, CA, United States, v. 68, p. 148–160, 1991. DOI: 10.7146/math.scand.a-12352. Disponível em: https://journals.msp.org/mscand/article/view/1276. Acesso em: 24 jul. 2026.