Prapai Klinkhachorn. (1993) A survey of problems and practices of teaching English in large classes. Mahidol University,:ม.ป.ท.Prapai Klinkhachorn. 1993. A survey of problems and practices of teaching English in large classes. ม.ป.ท.:Mahidol University,;Prapai Klinkhachorn. A survey of problems and practices of teaching English in large classes. ม.ป.ท.:Mahidol University, 1993. Print.