On the Interaction Between Closure Operations and Choice Functions with Applications to Relational Database. - János Demetrovics; G. Hencsey; Leonid Libkin; Ilya B. Muchnik (Acta Cybern., 1992)

Normal Form Relation Schemes: A New Characterization. - János Demetrovics; G. Hencsey; Leonid Libkin; Ilya B. Muchnik (Acta Cybern., 1992)