1. Department of Mathematics, Sungkyunkwan University, Suwon 16419, Gyeonggi-do, Republic of Korea
2. Department of Mathematics, Tamralipta Mahavidyalaya, Tamluk 721636, West Bengal, India
3. Division of Applied Mathematics, Wonkwang University, 460, Iksan-daero, Iksan-si 54538, Jeonbuk, Republic of Korea