JALAVA, V. Remarks on the regularity of the solutions of a linear partial differential equation with constant coefficients. Annales Fennici Mathematici, [S. l.], n. 530, 1973. DOI: 10.5186/aasfm.1973.530. Disponível em: https://afm.journal.fi/article/view/134186. Acesso em: 26 nov. 2024.