BONDARENKO, V. G.; PROKOPENKO, Yu. Yu. Barrier functions for one class of semilinear parabolic equations. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 60, n. 11, p. 1449–1456, 2008. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/3260. Acesso em: 7 dec. 2025.