RDF: Concepts and Abstract Syntax
URI: http://www.w3.org/TR/rdf-concepts/

Note: there is a previous Recommendation of 1999 that is

superseded by these

Note: there is a previous Recommendation of 1999 that is superseded by these

RDF Semantics
URI: http://www.w3.org/TR/rdf-mt/

Precise, graph based definition of the semantics

This is primarily for implementers

RDF/XML Serialization
URI: http://www.w3.org/TR/rdf-syntax-grammar/
N3 Serialization Primer
URI: http://www.w3.org/2000/10/swap/Primer

Note: this is not part of the W3C Recommendation track!