<http://schema.org/url>
<http://www.businessweek.com/articles/2013-07-11/in-probing-the-asiana-crash-ntsb-gets-busy-on-twitter>
<http://www.bloomberg.com/bw/articles/2013-07-11/in-probing-the-asiana-crash-ntsb-gets-busy-on-twitter>