LEUTWILER, H. On a distance invariant under Möbius transformations in Rn. Annales Fennici Mathematici, [S. l.], v. 12, n. 1, p. 3–17, 1987. DOI: 10.5186/aasfm.1987.1219. Disponível em: https://afm.journal.fi/article/view/134578. Acesso em: 25 nov. 2024.