MÜLLER, S.; STRUWE, M. Global existence of wave maps in $1 + 2$ dimensions with finite energy data. Topological Methods in Nonlinear Analysis, [S. l.], v. 7, n. 2, p. 245–259, 1996. Disponível em: https://apcz.umk.pl/TMNA/article/view/TMNA.1996.011. Acesso em: 22 lip. 2024.