NAZAROV, S. A.; SOKOLOWSKI, J.; TASKINEN, J. Neumann Laplacian on a domain with tangential components in the boundary. Annales Fennici Mathematici, [S. l.], v. 34, n. 1, p. 131–143, 2009. Disponível em: https://afm.journal.fi/article/view/135256. Acesso em: 14 may. 2024.