<https://goldpresidents.com/es/blogs/necklaces/doubling-your-game-your-guide-to-matching-chains-to-pendants#article>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://goldpresidents.com/es/blogs/necklaces/doubling-your-game-your-guide-to-matching-chains-to-pendants>