___

• [1] Atindogbe , C. Duggal, K.L.,Conformal screen on lightlike hypersurfaces, Int. J. Pure Appl. Math. 11(4), (2004), 421-442.
• [2] Chen, B.Y.,Classification of Surfaces with Planar Normal Sections, Journal of Geometry Vol.20 (1983) 122-127
• [3] Duggal, K. L. and Bejancu, A., Lightlike Submanifolds of Semi-Riemannian Manifolds and Applications, Kluwer Academic Publisher, 1996.
• [4] Duggal, K. L. and Jin, D. H., Null Curves and Hypersurfaces of Semi Riemannian Manifolds, World Scientific, 2007.
• [5] Duggal, K. L. and Sahin B., Differential Geometry of Lightlike Submanifolds, Springer Birkhauser, 2010.
• [6] Kim, Y. H.,Minimal surfaces of pseudo-Euclidean spaces with geodesic normal sections, Dif- ferential Geometry and its Applications 5 (1995) 321-329.
• [7] Kim, Y. H.,Pseudo-Riemannian Submanifolds with pointwise planar normal sections, Math. J. Okayama Univ.34 (1992), 249-257.
• [8] Kim, Y. H.,Surfaces in a pseudo-Euclidean space with planar normal sections, Journal of Geometry Vol.35 (1989),120-131.
• [9] Li. S. J.,Submanifolds with Pointwise Planar Normal Sections in a sphere, Journal of Geom- etry, 70 (2001) 101-107.
• [10] O’Neill , B., Semi Riemannian Geometry with Applications to Relativity, Academic Press,1983.