PORTNYAGIN, D. V. Boundedness of weak solutions of a nondiagonal singular parabolic system of three equations. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 58, n. 8, p. 1084–1096, 2006. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/3515. Acesso em: 14 apr. 2025.