<http://schema.org/tickerSymbol>
"NYSEMKT GDX"^^<http://www.w3.org/2001/XMLSchema#string>
<http://www.fool.com/investing/etf/2014/08/28/3-reasons-market-vectors-gold-miners-etf-could-fal.aspx?source=isesitlnk0000008>