[1] Univ Valencia, Fac Math, Dept Stat & Operat Res, C Dr Moliner 50, Burjassot 46100, Spain
[2] Univ Castilla La Mancha, Dept Math, ETS Ingn Ind Albacete, La Mancha Ave Espana,S-n, Albacete 02071, Spain
[3] Norwegian Sch Econ, Dept Econ, Helleveien 30, N-5045 Bergen, Norway
[4] Univ Bergamo, Dept Econ, Via Caniana 2, IT-24127 Bergamo, Italy
[5] King Abdullah Univ Sci & Technol, Thuwal, Saudi Arabia