Thắng, Đặng Quyết, Nguyễn Đình Hân, and Phan Trung Huy. 2012. “Determining Unambiguous Degree of Regular Languages by Automata”. Journal of Computer Science and Cybernetics 28 (1):53-64. https://doi.org/10.15625/1813-9663/28/1/1065.