Table 1.

Key W3C Specifications

Year	Technology	Description
1999	RDF	Resource Description Framework (RDF) Model and Syntax Specification [6]
2004	RDF/XML	RDF/XML Syntax Specification (Revised) [13]
	RDF	Resource Description Framework (RDF): Concepts and Abstract Syntax [32]
	OWL	OWL Web Ontology Language Overview [33]
2007	OWL2	OWL 2 Web Ontology Language Document Overview [33]
2008	RDFa	RDFa in XHTML: Syntax and Processing [16]
	SPARQL	SPARQL Query Language for RDF [19]

Several of the key specifications and when they were recommended by the World Wide Web Consortium.