Ek-Un และ Shannoy. (1990) Observation and analysis of question-asking behavior of Thai ESP teachers and student responses to those questions. Mahidol University,:ม.ป.ท.Ek-Un และ Shannoy. 1990. Observation and analysis of question-asking behavior of Thai ESP teachers and student responses to those questions. ม.ป.ท.:Mahidol University,;Ek-Un และ Shannoy. Observation and analysis of question-asking behavior of Thai ESP teachers and student responses to those questions. ม.ป.ท.:Mahidol University, 1990. Print.