<http://schema.org/mainEntityOfPage>
<http://www.upi.com/Top_News/US/2012/03/27/Santorum-expresses-doubt-on-winning-Wis/88261332831600/>
<http://www.upi.com/Top_News/US/2012/03/27/Santorum-expresses-doubt-on-winning-Wis/UPI-88261332831600/>