Chana, C., P. Hamelink, C. Chamswarng, S. Sangchote, U. Farungsang, R. Bunjoechoedchu, and U. Ongsakul. “Small Holders of Rubber-based Farming Systems in Songkhla Province Thailand : Problems and Potential Solutions”. Kasetsart Journal of Social Sciences, vol. 22, no. 1, Jan. 2001, pp. 79-97, https://so04.tci-thaijo.org/index.php/kjss/article/view/243515.