First Author:   Giam Quang Do Chiangmai University and Hanoi University of Agriculture giamdq.hua@gmail.com   E1/2-Ngo Xuan Quang Str., Trau Quy, Gia Lam Hanoi, 84, Vietnam   (84)904334525(Phone) (84)904334525(Fax) Second Author: Michael Mcaleer Erasmus University Rotterdam and National Chung Hsing University michael.mcaleer@gmail.com   Perth, Perth Western Australia 6000, Australia   (08) 9485 0002(Phone)   Third Author: Songsak Sriboonchitta Chiangmai University songsak@econ.cmu.ac.th   239 Huay Keaw road, Muang district Chiangmai, Thailand   (66)53-942208(Phone) (66)53-942202(Fax)