ARNOLD, V. I. On the problem of realization of a given Gaussian curvature function. Topological Methods in Nonlinear Analysis, [S. l.], v. 11, n. 2, p. 199–206, 1998. Disponível em: https://apcz.umk.pl/TMNA/article/view/TMNA.1998.013. Acesso em: 24 jan. 2022.