Local refinement techniques for elliptic problems on cell-centered grids. III. Algebraic multilevel BEPS preconditioners. R.D. Lazarov; R.E. Ewing; ... — 1991 Numerische Mathematik
Superconvergence analysis of approximate boundary-flux calculations. R.D. Lazarov; A.I. Pehlivanov; ... — 1992 Numerische Mathematik
On the Convergence of Difference Schemes for the Approximation of Solutions u...W... (m>0.5) of Elliptic Equations with Mixed Derivatives. R.D. Lazarov; V. Makarov; W. Weinelt — 1984 Numerische Mathematik