1. Department of Management and Law, Faculty of Economics, University of Rome Tor Vergata, Via Columbia, 2, 00133 Rome, Italy
2. Faculty of Sciences of Bizerte, University of Carthage, Bizerte 7021, Tunisia
3. Systems Engineering Department, Colorado State University, Fort Collins, CO 80523, USA
4. McGill Centre for the Convergence of Health and Economics, McGill University, 680 Sherbrooke, St. W., Montreal, QC H3A 0B8, Canada