Demetrovics, János, and Vu Duc Thi. “Some Problems Concerning Armstrong Relations of Dual Schemes and Relation Schemes in the Relational Datamodel”. Acta Cybernetica 11, no. 1-2 (January 1, 1993): 35-47. Accessed April 26, 2024. https://cyber.bibl.u-szeged.hu/index.php/actcybern/article/view/3419.