1. Max-Planck Institute for Dynamics of Complex Technical Systems , 39106 Magdeburg, Germany
2. Faculty of Technical Sciences , University of Novi Sad, Trg D. Obradovica 6, Novi Sad 21125, Serbia
3. Department of Mathematical Sciences , United Arab Emirates University, Al Ain P.O. Box 15551, UAE
4. Department of Mathematics , Guelma University, Guelma 24000, Algeria