GUSTAVSSON, Jan. Metrization of Quasi-Metric Spaces. MATHEMATICA SCANDINAVICA, [S. l.], v. 35, p. 56–60, 1974. DOI: 10.7146/math.scand.a-11536. Disponível em: https://tidsskrift.dk/math/article/view/11536. Acesso em: 13 aug. 2026.