GUSTAFSSON, B.; SAKAI, M. Sharp estimates of the curvature of some free boundaries in two dimensions. Annales Fennici Mathematici, [S. l.], v. 28, n. 1, p. 123–142, 2003. Disponível em: https://afm.journal.fi/article/view/135068. Acesso em: 11 may. 2024.