<https://www.under-the-cover.com/single-post/2015/06/11/557966490cf219f17735d4b1>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://www.under-the-cover.com/single-post/2015/06/11/The-EitherOr-Question>