Somboonsuke, B., C. Kongmanee, N. Thongtrai, and P. Phitthayaphinant. “Potential of Para-Rubber Production in Thailand: Production Technology Management, Problems and Suggestions for Yield Improvement”. Kasetsart Journal of Social Sciences, vol. 39, no. 1, Apr. 2018, pp. 645-59, https://so04.tci-thaijo.org/index.php/kjss/article/view/242476.