PIK, D. R.; KAASHOEK, M. A.; AROV, D. Z. Generalized solutions of Riccati equalities and inequalities. Methods of Functional Analysis and Topology, [S. l.], v. 22, n. 2, p. 95–116, 2016. Disponível em: https://zen.imath.kiev.ua/index.php/mfat/article/view/630. Acesso em: 4 feb. 2026.