1. Department of Statistics and Econometrics, Bucharest University of Economic Studies, Bucharest, Romania
2. Institute of National Economy – Romanian Academy, Bucharest, Romania
3. Department of Cybernetics, Economic Informatics, Finance and Accounting, Petroleum-Gas University of Ploiesti, Ploiești, Romania
4. Department of Economics,” Dunărea de Jos”, University of Galați, Galați, Romania