On sectional curvatures of ( ε ) -Sasakian manifolds. Kumar, Rakesh; Rani, Rachna; Nagaich, R.K. — 2007 International Journal of Mathematics and Mathematical Sciences
On CR-lightlike product of an indefinite Kaehler manifold. Kumar, Rakesh; Kaur, Jasleen; Nagaich, R.K. — 2011 International Journal of Mathematics and Mathematical Sciences