<https://nvctraining.com/nvc-library/articles/six-ways-to-check-if-an-allied-intervention-is-welcome>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://nvctraining.com/nvc-library/articles/six-ways-to-check-if-an-allied-intervention-is-welcome>