1. Department of Pharmaceutical Sciences, "Vasile Goldiş" Western University of Arad, Arad 310048, Romania
2. Department of Hospitality Services, Babeş-Bolyai University, Cluj-Napoca 400174, Romania
3. Department of Mathematics, Government College University, Lahore 54000, Pakistan
4. Department of Mathematics, Babeş-Bolyai University, Cluj-Napoca 400084, Romania