1. The Semantic Web
2. A translation approach to portable ontology specifications
3. Resource Description Framework (RDF) Model and Syntax Specificationhttps://www.w3.org/TR/1999/REC-rdf-syntax-19990222/
4. OWL Web Ontology Language Overviewhttps://www.w3.org/TR/owl-features/
5. Ontology Development 101: A Guide to Creating Your First Ontologyhttp://protege.stanford.edu/publications/ontology_development/ontology101.pdf