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Besse, A. L., Einstein Manifold, Springer-Verlag, (1987).
Chaki, M. C. and Maity, R. K.: On quasi-Einstein manifolds, Publ. Math. Debrecen, 57, pp.297-306 (2000).
Deszcz, R., Hotlo´s, M. and Sent¨urk, Z.: Quasi-Einstein hypersurfaces in semi-Riemannian space forms, Colloq. Math., 81, pp.81-97(2001).
Jana, S. K. and Shaikh, A. A.: On quasi-Einstein spacetime with space-matter tensor, Lobachevskii J. Math., 33(3), pp.255-261(2012).
Petrov, A. Z. : Einstein Spaces, Pergamon Press, Oxford, (1949).