Suwannatrai, L. . “Guidelines for Development of English Communicative Skills of Traders in Special Economic Zone (SEZ), Mueang District, Mukdahan Province”. International Journal of Development Administration Research, vol. 1, no. 1, Dec. 2020, pp. 19-30, https://so02.tci-thaijo.org/index.php/ijdar/article/view/246367.