<https://www.2y4t.com/foro/t/116045-beta-xtrainer-2021/#comment-1486021>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://www.2y4t.com/foro/t/116045-beta-xtrainer-2021/?tab=comments#comment-1485986>