1. http://www.w3.org/2004/OWL/; http://www.w3.org/2004/OWL/;
2. R. Studer; http://www.w3.org/TR/webont-req/; http://www.w3.org/TR/owl-features; R. Studer; http://www.w3.org/TR/webont-req/; http://www.w3.org/TR/owl-features;
3. J. Kelly The Essence of Logic Prentice Hall 1997; J. Kelly The Essence of Logic Prentice Hall 1997;
4. Protégé OWL Web Site; CO-ODE Web Site; Tim Berners-Lee James Hendler and Ora Lassila The Semantic Web Scientific American 2001; Protégé OWL Web Site; CO-ODE Web Site; Tim Berners-Lee James Hendler and Ora Lassila The Semantic Web Scientific American 2001;