Guangqi Li, Jianzhou Liu & Juan Zhang. (2020). The Disc Theorem for the Schur Complement of Two Class Submatrices with $γ$-Diagonally Dominant Properties.
            <i>Numerical Mathematics: Theory, Methods and Applications</i>. <i>10</i> (1).
            84-97.
         doi:10.4208/nmtma.2017.y14034