blogs.technet.com/b/speschka/archive/2012/07/23/using-query-rules-result-types-and-display-templates-for-a-custom-search-sales-report-in-sharepoint-2013.aspx
http://blogs.msdn.com/b/murads/archive/2012/10/11/utilizing-web-apps-2010-to-get-powerpoint-previews-of-sharepoint-2010-content-from-sharepoint-2013-search.aspx
http://www.wictorwilen.se/sharepoint-2013-enabling-pdf-previews-with-office-web-apps-2013-march-2013-update
http://social.msdn.microsoft.com/Forums/en-US/sharepointsearch/thread/f6a509f3-3ce6-4970-9dc8-7e6dc4f94507
http://www.bing.com/search?q=how+to+preview+pdf+in+sharepoint&qs=n&form=QBRE&pq=how+to+preview+pdf+in+sharepoint&sc=0-19&sp=-1&sk=