MANH, Le. Hệ GT89. <b>Journal of Computer Science and Cybernetics</b>, <i>[S. l.]</i>, v. 6, n. 1, p. 27–30, 2018. DOI: 10.15625/1813-9663/6/1/11136. Disponível em: https://jcc.vast.vn/jcc/article/view/11136. Acesso em: 4 nov. 2025.