This is a language which is a compact and readable alternative to RDF's XML syntax, but also is extended to allow greater expressiveness. It has subsets, one of which is RDF 1.0 equivalent, and one of which is RDF plus a form of RDF rules.
This Thinking XML column shows how to combine metadata collected from multiple XML source documents into a single Resource Description Framework (RDF) model for effective querying. In this follow-up to his previous installment that introduced how to use X
S. Bechhofer, R. Volz, and P. Lord. Proc. of the First International Semantic Web Conference 2003 (ISWC 2003), October 21-23, 2003, Sanibel Island, Florida, page 659-675. (2003)