PTASHNIK, B. I. Some Pseudoparabolic Variational Inequalities with Higher Derivatives. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 54, n. 1, p. 94–105, 2002. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/4043. Acesso em: 11 apr. 2025.