<http://schema.org/url>
<http://www.businessweek.com/articles/2013-03-07/mexicos-carlos-slim-is-still-the-richest-but-bill-gates-is-gaining>
<http://www.bloomberg.com/bw/articles/2013-03-07/mexicos-carlos-slim-is-still-the-richest-but-bill-gates-is-gaining>