1. School of Economics, Qingdao University, Qingdao, China
2. Department of Economics, Graduate Academy, Party School of the Central Committee of the Communist Party of China (National Academy of Governance), Beijing, China
3. Department of Non-communicable Chronic Disease, Qingdao Municipal Center for Disease Control & Preventation, Qingdao, China
4. Department of Finance, West University of Timisoara, Timisoara, Romania