<https://cs.2uandtrilogy.com/2616-sharpening-a-knife-with-another-knife-a-handy-tip>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://cs.2uandtrilogy.com/2616-sharpening-a-knife-with-another-knife-a-handy-tip>