WANG, James Li-ming. Modulus of Approximate Continuity for $R(X)$. Mathematica Scandinavica, Berkeley, CA, United States, v. 34, p. 219–225, 1974. DOI: 10.7146/math.scand.a-11522. Disponível em: https://journals.msp.org/mscand/article/view/2125. Acesso em: 25 jul. 2026.