<https://crew.org.nz/forum/index.php?/forums/topic/18764-new-engine-choice/page/2/#comment-249380>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://crew.org.nz/forum/index.php?/forums/topic/18764-new-engine-choice/page/2/&tab=comments#comment-249604>