<http://schema.org/about>
"It's basic economics that the price of goods and services should reflect (or \"internalize\") all the societal costs of those goods and services.  Yet the price of many products -- including electricity, gasoline and other fossil fuels -- frequently"^^<http://www.w3.org/2001/XMLSchema#string>
<http://www.treehugger.com/corporate-responsibility/an-inconvenient-tax.html>