TOAN, Nguyen Canh; LAP, Do Van. On the method of state invariance. Journal of Computer Science and Cybernetics, [S. l.], v. 11, n. 1, p. 39–48, 2016. DOI: 10.15625/1813-9663/11/1/8129. Disponível em: https://vjs.ac.vn/jcc/article/view/8129. Acesso em: 30 apr. 2025.