LITOVCHENKO, V. A. Cauchy problem for one class of pseudodifferential systems with entire analytic symbols. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 58, n. 9, p. 1211–1233, 2006. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/3523. Acesso em: 5 dec. 2025.