Ratree Charoenrat. 1998. effects of synthesis instruction on secondary school students' synthesis texts. Bangkok:National Institute of Development Administration;
Ratree Charoenrat. (1998) effects of synthesis instruction on secondary school students' synthesis texts (รายงานผลงานวิจัย). National Institute of Development Administration:Bangkok.
Ratree Charoenrat. effects of synthesis instruction on secondary school students' synthesis texts. Bangkok:National Institute of Development Administration, 1998.
Ratree Charoenrat. (1998) effects of synthesis instruction on secondary school students' synthesis texts (รายงานผลงานวิจัย). National Institute of Development Administration:Bangkok.