Tzanio V. Kolev  & Panayot S. Vassilevski. (2019). Parallel Auxiliary Space AMG for $\boldsymbol{H}$(Curl) Problems.
            <i>Journal of Computational Mathematics</i>. <i>27</i> (5).
            604-623.
         doi:10.4208/jcm.2009.27.5.013