Affiliation: | 1. School of Studies in Mathematics, Pt. Ravishankar Shukla University, Raipur (C. G.) 492010, India;2. Department of Mathematics Education and the RINS, Gyeongsang National University, Chinju 660-701, Republic of Korea;3. Department of Mathematics and the RINS, Gyeongsang National University, Chinju 660-701, Republic of Korea |