| Affiliation: | 1. Department of Physics, Chemistry and Mathematics, Alabama A&M University, Normal, AL 35762-7500, USA;2. Department of Mathematics, King Abdulaziz University, Jeddah 21589, Saudi Arabia;3. Department of Mathematics and Statistics, Tshwane University of Technology, Pretoria 0008, South Africa;4. Department of Mathematics, Lamar University, Beaumont, TX 77710, USA;5. Department of Mathematics, Howard University, Washington, DC 20059, USA;6. School of Electronics and Information Engineering, Wuhan Donghu University, Wuhan 430212, People''s Republic of China;7. Institute of Physics Belgrade, Pregrevica 118, 11080 Zemun, Serbia |
