HAN, Pham Van et al. “BRAINballs” educational balls - An innovative teaching method in education "Children learn while playing". VNU Journal of Science: Education Research, [S.l.], v. 36, n. 4, nov. 2020. ISSN 2588-1159. Available at: <https://js.vnu.edu.vn/ER/article/view/4443>. Date accessed: 23 dec. 2024. doi: https://doi.org/10.25073/2588-1159/vnuer.4443.