<https://www.edrmagazine.eu/northrop-grummans-autonomous-vtol-x-plane-advances-to-next-design-phase-for-darpa>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://www.edrmagazine.eu/northrop-grummans-autonomous-vtol-x-plane-advances-to-next-design-phase-for-darpa>