1. INRIA/Centre de mathématiques appliquées, École Polytechnique, Université Paris-Saclay, Palaiseau, France.
2. Laboratory Jacques Louis Lions, University Pierre et Marie Curie, Paris, France.
3. St. Petersburg State University, St. Petersburg, Russia.
4. Peter the Great St. Petersburg Polytechnic University, St. Petersburg, Russia.
5. Laboratory of Mathematical Methods in Mechanics of Materials, Institute of Problems of Mechanical Engineering, St. Petersburg, Russia.