1. School of Finance and Economics, Xi’an Jiaotong University, Xi’an 710061, China
2. Planning and Financial Department, Guangzhou Civil Aviation College, Guangzhou 510403, China
3. Department of Economics, Division of Management and Administrative Science, University of Education, Lahore 54770, Pakistan
4. Department of Agricultural Economics, Ondkuz Mayis University, Samsun 55139, Turkey