<http://www.w3.org/1999/02/22-rdf-syntax-ns#rest>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#nil>
<http://www.popularmechanics.com/science/health/a10512/x-y-scientists-create-two-new-letters-for-dna-16769967/?click=pm_news>