1. Delft Institute of Applied Mathematics, Faculty Electrical Engineering, Mathematics and Computer Science Delft University of Technology Delft The Netherlands
2. Departamento de Matemática ‐ Universidade Estadual de Maringá Maringá PR Brazil
3. Department of Mathematics and Statistics McMaster University Hamilton Ontario Canada
4. Department of Applied Mathematics Nizhny Novgorod State Technical University Nizhny Novgorod Russia