A Preconditioned Iterative Method for Saddlepoint Problems. - Torgeir Rusten; Ragnar Winther (SIAM J. Matrix Anal. Appl., 1992)

Interior penalty preconditioners for mixed finite element approximations of elliptic problems. - Torgeir Rusten; Panayot S. Vassilevski; Ragnar Winther (Math. Comput., 1996)

Domain Embedding and the Dirichlet Problem. - Einar Haug; Torgeir Rusten; Panayot S. Vassilevski; Ragnar Winther (LSSC, 1997)

Domain embedding preconditioners for mixed systems. - Torgeir Rusten; Panayot S. Vassilevski; Ragnar Winther (Numer. Linear Algebra Appl., 1998)