Junfeng Yin and Quanyu Dou. (2012). Generalized Preconditioned Hermitian and Skew-Hermitian Splitting Methods for Non-Hermitian Positive-Definite Linear Systems.
            <i>Journal of Computational Mathematics</i>. <i>30</i> (4).
            404-417.
         doi:10.4208/jcm.1201-m3209