___

• [1] Adati, T. and Miyazawa, T., On Riemannian space with recurrent conformal curvature. Tensor (N. S.), 18 (1967), 348-354.
• [2] Barros, A., Batista, R. and Ribeiro, E. Jr., Compact almost solitons with constant scalar curvature are gradient. Monatsh. Math., 174 Issue 1 (2014), 29-39.
• [3] Alias L. J., Romero, A. and Sanchez, M ., Uniqueness of complete spacelike of constant mean curvature in generalized Robertson-Walker spacetime. Gen. Rel. Grav., 27 (1995), 71–84.
• [4] Barros, A. and Riberiro, E. Jr., Some characterizations for compact almost Ricci solitons Proc. Amer. Math. Soc., 140 (2012), 1033-1040.
• [5] Brozos-Vazquez, M., Garcia-Rio, E. and Gavino-Fernandez, S., Locally conformally flat Lorentzian gradient Ricci solitons. J. Geom. Anal.,23 (2013), 1196-1212.
• [6] Chow, B. and Knopf, D., The Ricci flow: An Introduction. AMS, Providence, RI, USA, 2004.
• [7] Cao, H. D. Chow, B. Chu, S. C. and Yau, S. T(Editors)., Collected papers on Ricci Flow. Series in Geometry and Topology, Volume 37, International Press, Somervilla, Mass, USA, 2003.
• [8] Crasmareanu, M., Liouville and geodesic Ricci solitons. C. R. Acad. Sci. Paris, Ser., 347(2009), 1305-1308.
• [9] Derdzinski, A., Compact Riemannian manifolds with harmonic curvature and non-parallel Ricci tensor, Lecture Notes in Math., Vol. 838, Springer-Verlag, Berlin and New York, 1981.
• [10] Duggal, K. L., Symmetry inheritance in Riemannian manifolds with applications. Acta. Appl. Math., 31 (1993), 225-247.
• [11] Duggal, K. L., A new class of almost Ricci solitons and their physical interpretation. International Scholarly Research Notes, Volume 2016, Article ID 4903520, 6 pages.
• [12] Duggal, K. L. and Sharma, R., Symmetries of Spacetimes and Riemannian Manifolds. Kluwer Academic Publishers, 487, 1999.
• [13] Grycak, W., On affine collineations in conformally recurrent manifolds. Tensor N. S., 35 (1981), 45-50.
• [14] Hall, G. S. and Da-Costa, J., Affine collineations in spacetimes. J. Math. Phys., 29 (1988), 2465-2472.
• [15] Hamilton, R., Three-manifolds with positive Ricci curvature. J. Diff. Geom., 17(1982), 155-306.
• [16] Katzin, G. H., Levine, J. and Davis, W. R., Curvature collineations. J. Math. Phys., 10 (1969), 617-621.
• [17] Katzin, G. H., Levine, J. and Davis, W. R., Curvature collineations in conformally flat spaces, I. Tensor N.S., 21 (1970), 51-61.
• [18] Levine, J and Katzin, G. H., Conformally flat spaces admitting special quadratic first integrals, 1. Symmetric spaces. Tensor N. S., 19 (1968), 317-328.
• [19] Maartens, R. and Maharaj, S. D., Conformal Killing vectors in Robertson-Walker spacetimes. Class. Quant. Grav., 3 (1986), 1005-1011.
• [20] Maartens, R., Mason, D. P. and Tsamparlis, M., Kinematic and dynamic properties of conformal Killing vector fields in anisotropic fluids. J. Math. Phys., 27 (1986), 2987-2994.
• [21] Onda, K., Lorentz Ricci Solitons on 3-dimensional Lie groups, Geom. Dedicata, 147(2010), 313-322.
• [22] Petrov, A. Z., Einstein spaces. Pergamon Press, Oxford, 1969.
• [23] Pigola, S., Rigoli, M., Rimoldi, M. and Setti, A., Ricci almost solitons. Ann. Scuola Norm. Sup. Pisa CI. Sci., 5 X (2011), 757-799.
• [24] Sharma, R., Almost Ricci solitons and K-contact geometry. Montash Math., DOI 10.1007/s00605–014-0657-8, (2014).
• [25] Wang, Y., Gradient Ricci almost solitons on two classes of almost Kenmotsu manifolds. J. Korean Math. Soc., 53 N0. 5 (2016), 1101-1114.
• [26] Witten, E., String theory and black holes. Phys. Rev. ,D(3) 44, no. 2 (1991), 314-324.
• [27] Yano, K., Integral formulas in Riemannian geometry. Marcel Dekker, New York, 1970.