Affiliation: | 1. Mathematics Section, School of Distance Education, Universiti Sains Malaysia, 11800 USM Pulau Pinang, Malaysia;2. School of Mathematical Sciences, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor, Malaysia;3. Department of Mathematics, Babe?-Bolyai University, Cluj-Napoca 400084, Romania |