1. Center for Research on International Economics, Department of Economics, University of Wisconsin-Milwaukee, Milwaukee, WI, USA.
2. Department of Economics, College of Business, Economics and Computing, University of Wisconsin-Parkside, Kenosha, WI, USA
3. Department of Economics, Southern Illinois University Edwardsville, Edwardsville IL, USA.
4. School of Banking and Finance, University of International Business and Economics, Beijing, China.