LAVRENYUK, S. P.; PTASHNIK, B. I. On certain nonlinear pseudoparabolic variational inequalities without initial conditions. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 51, n. 3, p. 328–337, 1999. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/4616. Acesso em: 7 apr. 2025.