Suwanthanin , W. (2022) “Closed-Door Policy of the Qing Dynasty and China’s Defeat in the First Opium War ”, Journal of ASEAN PLUS Studies, 3(2), pp. 1–12. available at: https://so06.tci-thaijo.org/index.php/aseanplus/article/view/260427 (accessed: 21 September 2026).