Foundations of Rule−Based Query Answering by Bry, F, Eisinger, N, Eiter, T, Furche, T, Gottlob, G, Ley, C, Linse, B, Pichler, R, Wei, F

“…These results have later formed the basis for conceiving, improving, and implementing several Web and Semantic Web technologies, in particular query languages such as XQuery or SPARQL for querying relational, XML, and RDF data, and rule languages like the “Rule Interchange Framework (RIF)” currently being developed in a working group of the W3C. …”