KITTIPALO, P. K.; PLOYSAENG, K. Principles and Art of Speaking. Mahachula Academic Journal, Bangkok, Thailand, v. 5, n. ฉบับพิเศษ, p. 40–51, 2018. Disponível em: https://so04.tci-thaijo.org/index.php/JMA/article/view/141269. Acesso em: 1 may. 2024.