<https://itexpert.edu.gr/tag/%cf%80%ce%b9%cf%83%cf%84%ce%bf%cf%80%ce%bf%ce%af%ce%b7%cf%83%ce%b7-ecdl/#webpage>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://itexpert.edu.gr/tag/%CF%80%CE%B9%CF%83%CF%84%CE%BF%CF%80%CE%BF%CE%AF%CE%B7%CF%83%CE%B7-ecdl/>