Kasetkasem, S., P. Boonruang, V. Lertmongkol, A.-O. Aungsuratana, J. Wattana, S. Pattratham, and S. Pramsopee. “ Kasetsart University Research and Development Institute”. Kasetsart Journal of Social Sciences, vol. 16, no. 2, July 1995, pp. 156-67, https://so04.tci-thaijo.org/index.php/kjss/article/view/243716.