ANTYPKO, I. I. A theorem of the Phragmén-Lindelöf type for solutions of an evolution equation of the second order with respect to time variable. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 50, n. 5, p. 724–731, 1998. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/4910. Acesso em: 5 dec. 2025.