1. Qiaohua Liu, Xianjuan Li, Preconditioned conjugate gradient methods for the solution of indefinite least squares problems, Calcolo, 48(3):2011, 261-271.
2. Qiaohua Liu, Modified Gram-Schmidt-based methods for block downdating the Cholesky factorization, J. Comput. Appl. Math., 235(8): 2011, 1897-1905.
3. Qiaohua Liu, Baozhen Pan, Qian Wang, The hyperbolic elimination method for solving the equality constrained indefinite least squares problem, Int. J. Comput. Math, 87:13(2010), 2953–2966.
4. Qiaohua Liu, Minghui Wang, Algebraic properties and perturbation results for the indefinite least squares problem with equality constraints, Int. J. Comput. Math., 87: 2(2010), 425 - 434.
5. Qiaohua Liu, Musheng Wei, Reverse order law for least，squares g-inverses of multiple matrix products, Linear and Multilinear algebra, 2008, 56(5):491-506.