1. Department of Economics, The University of the West Indies, I, St. Augustine, Trinidad & Tobogo
2. Nanjing University of Aeronautics and Astronautics, P. R. China
3. Department of Economics, Hong Kong Baptist University, Kowloon Tang, Hong Kong
4. School of Statistics, Beijing Normal University, China
5. Department of mathematics, Hong Kong Baptist University, Kowloon Tang, Hong Kong