LILLEBERG, L. Factorizations of generalized Schur functions and products of passive systems. Methods of Functional Analysis and Topology, [S. l.], v. 28, n. 1, p. 66–88, 2022. Disponível em: https://zen.imath.kiev.ua/index.php/mfat/article/view/820. Acesso em: 15 dec. 2025.