1. Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu, China
2. Department of Mathematics, University of British Columbia, Kelowna, B.C., Canada
3. Department of Mathematics and Computer Science, Faculty of Science and Technology, Rajamangala University of Technology Thanyaburi (RMUTT), Pathumthani, Thailand
4. School of Science, University of Phayao, Phayao, Thailand
5. Department of Mathematics Education and the RINS, Gyeongsang National University, Jinju, Korea
6. Center for General Education, China Medical University, Taichung, Taiwan