B. C. Chanyal

Department of Physics, G.B. Pant University of Agriculture & Technology, Pantnagar-263145 (U.K.) India

S. K. Chanyal

Department of Mathematics, Kumaun University, D.S.B. Campus Nainital-263001 (U.K.) India

Virendra Singh

Department of Physics, G.B. Pant University of Agriculture & Technology, Pantnagar-263145 (U.K.) India

A. S. Rawat

Department of Physics, H.N.B. Garhwal University, Pauri Campus Pauri-246001 (U.K.) India