Institution: | 1.Department of Mathematical Sciences, University of Alabama in Huntsville, 301 Sparkman Drive, Huntsville, AL, 35899, USA ;2.Department of Mathematics and Statistics, King Fahd University of Petroleum and Minerals, P.O.Box 5046, Dhahran, 31261, Saudi Arabia ;3.Department of Mathematics, University of Sharjah, P.O.Box 27272, Sharjah, United Arab Emirates ; |