<https://forum.norcom.pl/index.php?/topic/10737-zbie%C5%BCno%C5%9B%C4%87/#comment-200032>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://forum.norcom.pl/index.php?/topic/10737-zbie%C5%BCno%C5%9B%C4%87/>