Wantana Sa-adpan และ Damrong Attaprechakul. (2008) A study of factors affecting the English proficiency of non-native English speaking students at the Asian Institute of Technology. Language Institute, Thammasat University,:ม.ป.ท.Wantana Sa-adpan และ Damrong Attaprechakul. 2008. A study of factors affecting the English proficiency of non-native English speaking students at the Asian Institute of Technology. ม.ป.ท.:Language Institute, Thammasat University,;Wantana Sa-adpan และ Damrong Attaprechakul. A study of factors affecting the English proficiency of non-native English speaking students at the Asian Institute of Technology. ม.ป.ท.:Language Institute, Thammasat University, 2008. Print.