1. Singidunum University, Danijelova, Belgrade, Serbia
2. Technical faculty “Mihajlo Pupin”, University of Novi Sad, Dure Dakovica bb, Zrenjanin, Serbia
3. Department of Mathematics, Saveetha School of Engineering, SIMATS, Thandalam, Tamil Nadu, India
4. MEU Research Unit, Middle East University, Amman, Jordan