<http://schema.org/topics>
"amazon,barnes and noble,barnes &amp;amp; noble,borders,Business,copia,e-books,e-commerce,earnings,ebooks,kindle,news,nook,quarterly earnings"^^<http://www.w3.org/2001/XMLSchema#string>
<http://mashable.com/2010/08/24/barnes-and-noble-earnings-q1-2011/>