Ratree Charoenrat. (1998) <The> effects of synthesis instruction on secondary school students' synthesis texts. National Institute of Development Administration:ม.ป.ท.Ratree Charoenrat. 1998. <The> effects of synthesis instruction on secondary school students' synthesis texts. ม.ป.ท.:National Institute of Development Administration;Ratree Charoenrat. <The> effects of synthesis instruction on secondary school students' synthesis texts. ม.ป.ท.:National Institute of Development Administration, 1998. Print.