- The official source, the w3c provides introductory material on the basic concepts of the semantic web https://www.w3.org/standards/semanticweb/
- The w3c has a working group that has some ideas about translating Relational databases into RDF datasets at: https://www.w3.org/TR/r2rml/
- From the source: https://www.w3.org/TR/sparql11-query/