1. Department of Mathematics, Hajee Mohammad Danesh Science and Technology University, Dinajpur, Bangladesh
2. Department of Applied Mathematics, University of Rajshahi, Rajshahi, Bangladesh
3. Department of International Trade, Çankırı Karatekin University, Cankiri, Turkey
4. Neighborhood of Akcaglan, No. 28/4, Imarli Street, 26030 Eskisehir, Turkey