ELIASSON, Halldór I. On Variations of Metrics. MATHEMATICA SCANDINAVICA, [S. l.], v. 29, p. 317–327, 1971. DOI: 10.7146/math.scand.a-11058. Disponível em: https://tidsskrift.dk/math/article/view/11058. Acesso em: 14 aug. 2026.