1. S.L. Campbell, C.D. Meyer, Generalized inverses of linear transformations, Pitman, London, 1979, Dover, New York, 1991.
2. A. Ben-Israel, T.N.E. Greville, Generalized Inverses: theory and applications, second ed., Wiley, New York, 1974, Springer-Verlag, New York, 2003.
3. The Drazin inverse and systems of second order linear differential equations;Campbell;Linear Multilinear Algebra,1983
4. On group inverse of singular Toeplitz matrices;Wei;Linear Algebra Appl.,2005
5. On group inverses of M-matrices with uniform diagonal entries;Kirkland;Linear Algebra Appl.,1999