<https://adolphesax.com/saxforo/threads/escuchar-leer-y-tocar.224125/>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://adolphesax.com/saxforo/threads/escuchar-leer-y-tocar.224125/page-12#post-333104>