| Affiliation: | 1. Dipartimento di Matematica, Università degli Studi di Bari “Aldo Moro”, Via Orabona 4, I-70125 Bari, Italy;2. Faculdade de Matemática, Universidade Federal do Pará, 66075-110, Belém, PA, Brazil;1. School of Mathematics and Physics, Shanghai Normal University, Shanghai 200234, PR China;2. Department of Mathematics, East China University of Science and Technology, Shanghai 200237, PR China;3. School of Mathematical Sciences, Zhejiang University, Hangzhou 310027, PR China;1. Department of Economics, Babeş-Bolyai University, Cluj-Napoca, Romania;2. Institute of Applied Mathematics, Óbuda University, 1034 Budapest, Hungary;1. Department of Mathematics, University of Craiova, 200585 Craiova, Romania;2. Research group of the project PN-II-ID-PCE-2012-4-0021, “Simion Stoilow” Institute of Mathematics of the Romanian Academy, P.O. Box 1-764, 014700 Bucharest, Romania;3. Department of Mathematics, Babeş-Bolyai University, 400084, Cluj-Napoca, Romania;1. Mathematical Sciences, University of Southampton, Highfield, Southampton SO17 1BJ, UK;2. Department of Mathematics and Statistics, Pennsylvania State University, Altoona College, Altoona, PA 16601, USA |
