1. LMPT, Fédération Denis Poisson, Université François-Rabelais Tours, France. E-mail: Guy.Barles@lmpt.univ-tours.fr
2. IRMAR, INSA Rennes, France
3. Dipartimento di Matematica, Università di Padova, Italy. E-mail: ttnguyen@math.unipd.it
4. Faculty of Mathematics and Statistics, Ton Duc Thang University, Ho Chi Minh City, Vietnam. E-mail: phanthanhviet@tdt.edu.vn