<http://www.chavannichap.com/2008/07/blog-post_11.html>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://www.chavannichap.com/search/label/%E0%A4%AE%E0%A4%B9%E0%A4%AC%E0%A5%82%E0%A4%AC%E0%A4%BE>