<https://forums.phpfreaks.com/topic/315059-what-did-i-wrong-in-scoping-not-working/>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://forums.phpfreaks.com/topic/315059-what-did-i-wrong-in-scoping-not-working/#comment-1598386>