Affiliation: | 1. Department of Mathematical Sciences, Delaware State University, Dover, DE 19901-2277, USA;2. Department of Mathematics, Faculty of Science, King Abdulaziz University, Jeddah 21589, Saudi Arabia;3. Canino School of Engineering Technology, State University of New York, Canton, NY 13617, USA;4. Department of Mathematics, Howard University, Washington, DC 20059, USA;5. Science Program, Texas A & M University at Qatar, PO Box 23874, Doha, Qatar |