<https://tut.gr/category/%ce%94%ce%b9%ce%b1%cf%83%ce%b7%ce%bc%cf%8c%cf%84%ce%b7%cf%84%ce%b5%cf%82/>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://tut.gr/%CF%85%CF%80%CE%AD%CF%81%CE%BF%CF%87%CE%B7-michelle-marie-claire/>