1. Department of Mathematics Alexandru Ioan Cuza University of Iaşi Iaşi Romania
2. Octav Mayer Institute of Mathematics Romanian Academy Iaşi Romania
3. Head of Lehrstuhl für Nichtlineare Analysis und Modellierung, Fakultät für Mathematik Universität Duisburg‐Essen, Campus Essen Essen Germany
4. Faculty of Mathematics and Information Science Warsaw University of Technology Warsaw Poland