<http://schema.org/mainEntityOfPage>
<http://www.upi.com/Sports_News/2009/09/14/Del-Potro-upsets-Federer-to-win-US-Open/61341252976694/>
<http://www.upi.com/Sports_News/2009/09/14/Del-Potro-upsets-Federer-to-win-US-Open/UPI-61341252976694/>