First Author:   Poomthan Rangkakulnuwat Faculty of Economics, Kasetsart University, Thailand poomthan@gmail.com         Second Author: Rungravee Weravess School of Economics, University of the Thai Chamber of Commerce rungravee_wer@utcc.ac.th   126/1 Vibhavadee-Rangsid Rd Dindaeng, 10400, Thailand   662-697-6305(Phone) 662-277-4359(Fax)