1. A generalized SSOR method;Axelsson;BIT,1972
2. On preconditioning and convergence acceleration in sparse matrix problems;Axelsson;CERN,1974
3. Conjugate gradient type methods for unsymmetric and inconsistent systems of linear equations;Axelsson;Linear Algebra Appl.,1980
4. Conjugate gradient methods for partial differential equations;Chandra;Adv. Comp. Meth. PDE's, AICA,1975
5. A generalized conjugate gradient method for the numerical solution of elliptic partial differential equations;Concus,1976