1. Department of Mathematics and Statistics, Faculty of Science, Universiti Putra Malaysia, Serdang, Malaysia
2. Institute for Mathematical Research, Universiti Putra Malaysia, Serdang, Malaysia
3. Fakulti Teknologi dan Kejuruteraan Industri dan Pembuatan, Universiti Teknikal Malaysia Melaka, Malaysia
4. Fakulti Teknologi dan Kejuruteraan Mekanikal, Universiti Teknikal Malaysia Melaka, Malaysia
5. Department of Mathematics, Babeş-Bolyai University, Cluj-Napoca, Romania
6. Academy of Romanian Scientists, Bucharest, Romania