1. Faculty of Cybernetics, Statistics and Economic Informatics, Department of Statistics and Econometrics, Bucharest University of Economic Studies, 6 Piata Romana, 1st District, 010374 Bucharest, Romania
2. Faculty of Finance and Accounting, Artifex University of Bucharest, 47 Economu Cezărescu Street, 6st District, 060754 Bucharest, Romania
3. Faculty of Economic Sciences, Department of Cybernetics, Economic Informatics, Finance and Accounting, Petroleum—Gas University of Ploiesti, 39 Bucharest Boulevard, 100680 Ploieşti, Romania
4. Department of Econometrics and Economic Statistics, Academy of Economic Sciences of Moldova, Str. Banulescu-Bodoni 61, MD-2005 Chișinău, Moldova