A. Dziekonski, M. Rewienski, P. Sypek, A. Lamecki and M. Mrozowski. (2017). GPU-Accelerated LOBPCG Method with Inexact Null-Space Filtering for Solving Generalized Eigenvalue Problems in Computational Electromagnetics Analysis with Higher-Order FEM. Communications in Computational Physics. 22 (4). 997-1014. doi:10.4208/cicp.OA-2016-0155