1. Abiteboul, S., Hull, R., Vianu, V.: Foundations of Databases. Addison-Wesley (1995)
2. Baget, J., Mugnier, M., Rudolph, S., Thomazo, M.: Walking the Complexity Lines for Generalized Guarded Existential Rules. In: IJCAI, pp. 712–717 (2011)
3. Lecture Notes in Computer Science;C. Beeri,1981
4. Borgida, A., Serafini, L.: Distributed Description Logics: Assimilating Information from Peer Sources. J. Data Semantics 1, 153–184 (2003)
5. Lecture Notes in Computer Science;P. Bouquet,2003