Xie , Yingxiong Xiao, Heng Chen and Lingjie. (2019). Two-Level Hierarchical PCG Methods for the Quadratic FEM Discretizations of 2D Concrete Aggregate Models.
Advances in Applied Mathematics and Mechanics. 11 (6).
1376-1397.
doi:10.4208/aamm.OA-2019-0002