HUANG, Zhuo-Hong; HUANG, Ting-Zhu. A constraint preconditioner for solving symmetric positive definite systems and application to the helmholtz equations and poisson equations. Mathematical Modelling and Analysis, [S. l.], v. 15, n. 3, p. 299–311, 2010. DOI: 10.3846/1392-6292.2010.15.299-311. Disponível em: https://journals.vilniustech.lt/index.php/MMA/article/view/6024. Acesso em: 9 may. 2025.