Institution: | 1. Institute for Computational and Experimental Research in Mathematics, Providence, RI, 02903 USA;2. Department of Mathematics, Faculty of Basic Sciences, University of Maragheh, P.O. Box 55136-553, Maragheh, Iran;1. Department of Mathematics and Computer Sciences, University Larbi Ben M''hidi, Oum El Bouaghi, Algeria;2. Department of Mathematics, University Kasdi Merbah-Ouargla, Ouargla, Algeria |