Zhong-Yun Liu Lu Lin Chun-Chao Shi Nonstationary two-stage multisplitting methods for symmetric positive definite matrices. 49-54 2000 13 Appl. Math. Lett. 8 http://dx.doi.org/10.1016/S0893-9659(00)00095-1 db/journals/appml/appml13.html#LiuLS00