1. Institut für Angewandte Mathematik, Leibniz University Hannover, Hannover, Germany
2. Faculty of Mathematics and Computer Science, Babeş-Bolyai University, Cluj-Napoca, Romania
3. Department of Mathematics, Technical University of Cluj-Napoca, Cluj-Napoca, Romania
4. Institute of Advanced Studies In Science and Technology, Cluj-Napoca, Romania
5. Tiberiu Popoviciu Institute of Numerical Analysis, Romanian Academy, Cluj-Napoca, Romania