Department of Mathematics, Tuskegee University, Tuskegee, AL, USA
Department of Mathematics, Tuskegee University, Tuskegee, AL, USA
Copyright © 2016 Youngsoo Kim, Byunghoon Lee et al. This is
an open access article distributed under the Creative Commons Attribution
License, which permits unrestricted use, distribution, and reproduction in any
medium, provided the original work is properly cited.