<http://schema.org/about>
"Last month a Unmanned Aerial Vehicle (UAV) made a High-Altitude Long-Endurance (HALE) flight powered by liquid hydrogen. The prototype fifty-foot wingspan aircraft stayed up for a hour on the test flights, but if we read the press release correctly, the"^^<http://www.w3.org/2001/XMLSchema#string>
<http://www.treehugger.com/cars/the-global-observer-hydrogen-gets-airborne.html>