<https://forum.catsbit.com/index.php?/topic/416-%D1%83%D1%80%D0%BE%D0%BD/>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://forum.catsbit.com/index.php?/topic/416-%D1%83%D1%80%D0%BE%D0%BD/&tab=comments>