SAPRIKIN, S. M. Generalized invertible selfadjoint solutions of Kalman-Yakubovich-Popov inequality and Riccati inequality, with finite negative spectrum. Methods of Functional Analysis and Topology, [S. l.], v. 8, n. 3, p. 72–84, 2002. Disponível em: https://zen.imath.kiev.ua/index.php/mfat/article/view/194. Acesso em: 17 dec. 2025.