Schur Complement Based Preconditioners for Twofold and Block Tridiagonal Saddle Point Problems. Communications in Mathematical Research, [S. l.], v. 40, n. 2, p. 214–244, 2024. DOI: 10.4208/cmr.2023-0051. Disponível em: https://global-sci.com/index.php/cmr/article/view/9125. Acesso em: 5 dec. 2025.