Naiyana Ponim. (1993) A comparative study of controlled and free writing English compositions of M.6 students. Mahidol University,:ม.ป.ท.Naiyana Ponim. 1993. A comparative study of controlled and free writing English compositions of M.6 students. ม.ป.ท.:Mahidol University,;Naiyana Ponim. A comparative study of controlled and free writing English compositions of M.6 students. ม.ป.ท.:Mahidol University, 1993. Print.