LAVRENYUK, S. P. Systems of parabolic variational inequalities without initial conditions. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 49, n. 4, p. 540–547, 1997. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/5029. Acesso em: 5 dec. 2025.