Are you talking about this paper: <a href="http:&#x2F;&#x2F;research.google.com&#x2F;pubs&#x2F;pub43146.html" rel="nofollow">http:&#x2F;&#x2F;research.google.com&#x2F;pubs&#x2F;pub43146.html</a>? It appears to be the same as the linked PDF.