Thuần, Hồ, Souafi Souad, and Mohamed Benkada Djamila. “Some More Properties and Remarks about Keys for Relation Scheme”. <i>Journal of Computer Science and Cybernetics</i> 12, no. 4 (April 6, 2016): 101–113. Accessed April 4, 2026. https://cip.vast.vn/jcc/article/view/8097.