GUSTAVSSON, Jan. Metrization of Quasi-Metric Spaces. Mathematica Scandinavica, Berkeley, CA, United States, v. 35, p. 56–60, 1974. DOI: 10.7146/math.scand.a-11536. Disponível em: https://journals.msp.org/mscand/article/view/2111. Acesso em: 25 jul. 2026.