1. A grid coarsening algorithm for unstructured multigrid applications
2. 4Ollivier-Gooch.,C.F."RobustCoarseningofUnstructuredMeshesforMultigridMethods,"AIAA-99-3250,1999
3. 5Mavriplis.,D.J."OnConvergenceAccelerationTechniquesForUnstructuredMeshes,"AIAA1998-2966,1998