VỴ, Nguyễn Văn; ĐỨC, Đặng Văn; ĐỨC, Nguyễn Mạnh. A relational algebraical model of object oriented systems. Journal of Computer Science and Cybernetics, [S. l.], v. 21, n. 3, p. 261–270, 2012. DOI: 10.15625/1813-9663/21/3/1250. Disponível em: https://vjs.ac.vn/jcc/article/view/1250. Acesso em: 30 apr. 2025.