Denchai Prabjandee และ Jutarat Vibulphol. (2009) Effects of using an english language counseling program on self-directed learning of upper secondary school students /. Chulalongkorn University,:ม.ป.ท.Denchai Prabjandee และ Jutarat Vibulphol. 2009. Effects of using an english language counseling program on self-directed learning of upper secondary school students /. ม.ป.ท.:Chulalongkorn University,;Denchai Prabjandee และ Jutarat Vibulphol. Effects of using an english language counseling program on self-directed learning of upper secondary school students /. ม.ป.ท.:Chulalongkorn University, 2009. Print.