I googled a few sites, every site points the link which says not available, for example, click download the package now Download the package now.on this link
http://webcache.googleusercontent.com/search?q=cache:ZGZ4ImXfGUgJ:https://www.microsoft.com/en-us/download/details.aspx%3Fid%3D49996+&cd=2&hl=en&ct=clnk&gl=ca
https://support.microsoft.com/en-us/kb/3072779
SQL Server 2012 SP3, Microsoft SQL Server 2012 Service Pack 3 (SP3) Express, and Microsoft SQL Server 2012 Service Pack 3 (SP3) Feature Pack are available for manual download and installation at the following Microsoft Download Center websites.| SQL Server 2012 SP3 |  Download
the package now. |
will get the page below
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