I. Ahmad
Department of Mathematics, University of Malakand, Chakdara, DirLower, Pakistan
R. Naz
Department of Mathematics, University of Malakand, Chakdara, Dir Lower, Pakistan
M. Rashad
Department of Mathematics, University of Malakand, Chakdara, Dir Lower, Pakistan
A. Khan
Department of Computer Science, University of Malakand, Chakdara, Pakistan