<http://c4dkorea.co.kr/blog/2018/11/08/tip-219-how-to-control-vertex-maps-with-fields/#article>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<http://c4dkorea.co.kr/blog/2018/11/08/tip-219-how-to-control-vertex-maps-with-fields/>