1. Abiteboul, S., Hull, R., Vianu, V.: Foundations of Databases. Addison Wesley Publ. Co., Reading (1995)
2. Acciarri, A., Calvanese, D., De Giacomo, G., Lembo, D., Lenzerini, M., Palmieri, M., Rosati, R.: QuOnto: querying ontologies. In: Proceedings of the 20th National Conference on Artificial Intelligence (AAAI 2005), pp. 1670–1671 (2005)
3. Ahmetaj, S., Fischl, W., Pichler, R., Šimkus, M., Skritek, S.: Towards reconciling SPARQL and certain answers. In: Proceedings of the 24th International Conference on World Wide Web, WWW 2015, Florence, Italy, 18–22 May 2015, pp. 23–33 (2015)
4. Lecture Notes in Computer Science;R Angles,2008
5. Antonioli, N., Castanò, F., Coletta, S., Grossi, S., Lembo, D., Lenzerini, M., Poggi, A., Virardi, E., Castracane, P.: Ontology-based data management for the Italian Public Debt. In: Proceedings of 8th International Conference Formal Ontology in Information Systems (FOIS 2014). Frontiers in Artificial Intelligence and Applications, vol. 267, pp. 372–385. IOS Press (2014)