22 July 2008 | Updated on 18 March 2016
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<p>© Copyright 2006 <span class="caps">SASI</span> Group (University of Sheffield) and Mark Newman (University of Michigan).<br />
<a href="http://www.worldmapper.org/" title="http://www.worldmapper.org/">http://www.worldmapper.org/</a></p>