PURMONEN, V. T. Parbolic pseudo-differential initial-boundary value problems. MATHEMATICA SCANDINAVICA, [S. l.], v. 65, p. 221–244, 1989. DOI: 10.7146/math.scand.a-12280. Disponível em: https://www.mscand.dk/article/view/12280. Acesso em: 7 may. 2024.