CHINNI, G. On the regularity of the solutions and of analytic vectors for “sums of squares”. Bruno Pini Mathematical Analysis Seminar, [S. l.], v. 13, n. 1, p. 90–108, 2022. DOI: 10.6092/issn.2240-2829/16159. Disponível em: https://mathematicalanalysis.unibo.it/article/view/16159. Acesso em: 25 apr. 2024.