Yue , XiaoqiangZhang , ShuleiXu , XiaowenShu , Shi and Shi , Weidong. (2021). Algebraic Multigrid Block Preconditioning for Multi-Group Radiation Diffusion Equations.
            <i>Communications in Computational Physics</i>. <i>29</i> (3).
            831-852.
         doi:10.4208/cicp.OA-2020-0030