2018. A Study of Preconditioned Jacobian-Free Newton-Krylov Discontinuous Galerkin Method for Compressible Flows on 3D Hexahedral Grids. Advances in Applied Mathematics and Mechanics. 10, 2 (Sept. 2018), 261–274. DOI:https://doi.org/10.4208/aamm.OA-2017-0004.