Vu Thi Khanh Linh, P. T. N. L. M. N. K. N. T. (2019) “The psychological stress of secondary school students in Vietnam”, Opción, 340, pp. 259-287. Available at: https://produccioncientificaluz.org/index.php/opcion/article/view/24295 (Accessed: 5December2025).