<https://backswing.com/answers/the-main-reason-for-the-change-in-rules-is-to-speed-up-play/>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://backswing.com/answers/the-main-reason-for-the-change-in-rules-is-to-speed-up-play/>