<http://schema.org/about>
"One teething problem in the burgeoning biofuel industry is the issue of sustainability: Some biofuels actually increase greenhouse gas emissions while being claimed to prevent them; others add to food price"^^<http://www.w3.org/2001/XMLSchema#string>
<http://www.treehugger.com/renewable-energy/sustainable-biodiesel-alliance-sets-out-draft-principles-for-sustainability-practices.html>