[1] Spiru Haret Univ, Dept Econ Sci, Bucharest 030167, Romania
[2] Univ Phys Educ & Sports, Doctoral Sch, CP 060057, Bucharest, Romania
[3] Inst Politecn Braganca, P-5300253 Braganca, Portugal
[4] Univ Business Acad, Fac Econ & Engn Management, Novi Sad 21000, Serbia
[5] Spiru Haret Univ, Fac Vet Med, Bucharest 030045, Romania
[6] Hyper Univ, Fac Econ Sci, Bucharest 030615, Romania