Jianguo Xin, Nailong Guo, and Wei Cai. (2011). On the Construction of Well-Conditioned Hierarchical Bases for Tetrahedral $\mathcal{H}{(curl)}$-Conforming Nédélec Elements.
            <i>Journal of Computational Mathematics</i>. <i>29</i> (5).
            526-542.
         doi:10.4208/jcm.1103-m3464