1. Department of Mathematics, College of Education of Jubail, Imam Abdulrahman Bin Faisal University, P.O. 12020, Industrial Jubail 31961, Saudi Arabia
2. Department of Medical Research, China Medical University Hospital, China Medical University, Taichung, Taiwan
3. Vojnogeografski Institut, Beograd, Vojska Srbije, Serbia
4. First Technical School, 35 000 Jagodina, Serbia
5. Department of Mathematics and Statistics, International Islamic University, Islamabad, Pakistan