1. Department of Mathematics, Government College Women University, Sialkot 51310, Pakistan
2. Department of Mathematics, University of the Punjab, Lahore 54590, Pakistan
3. Department of Hospitality Services, Babeş-Bolyai University of Cluj-Napoca, Horea Street, No. 7, 400174 Cluj-Napoca, Romania
4. Department of Pharmaceutical Sciences, “Vasile Goldiş” Western University of Arad, L. Rebreanu Street, No. 86, 310048 Arad, Romania