<http://schema.org/url>
<http://www.joystiq.com/2013/02/06/newell-valve-looking-to-make-portal-or-half-life-move-with-j-j/>
<http://www.engadget.com/2013/02/06/newell-valve-looking-to-make-portal-or-half-life-move-with-j-j/>