<http://schema.org/about>
"OK, admittedly it's pretty tough to gather reliable data from an erupting volcano, but we're suckers for a graph and the folks over at Information is Beautiful have been busy crunching"^^<http://www.w3.org/2001/XMLSchema#string>
<http://www.treehugger.com/clean-technology/volcano-vs-planes-the-emission-equation.html>